Inhaler

ABSTRACT

A inhaler includes a piezoelectric element substrate having an IDT constructed by use of a pair of interlocking comb-shaped metallic electrodes, a liquid supplier for supplying liquid, which is to be atomized, to a front surface of the piezoelectric element substrate on which the pair of interlocking comb-shaped metallic electrodes is positioned, a sensor, which includes at least a pair of detection parts which are opposite to each other, for detecting liquid supplied to the front surface of the piezoelectric element substrate, and a controller for controlling, based on result of detection by the sensor, the liquid supplier in such a manner that the liquid supplier supplies a certain quantity of the liquid to the front surface of the piezoelectric element substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of InternationalApplication No. PCT/JP2019/015382, filed on Apr. 9, 2019.

TECHNICAL FIELD

The present invention relates to an inhaler.

BACKGROUND ART

Conventionally, known is an atomizing unit configured to atomize liquidby using a piezoelectric element substrate having an IDT (interdigitaltransducer) made of a pair of interlocking comb-shaped electrodes togenerate a SAW (Surface Acoustic Wave) (for example, Patent Documents 1and 2). Further, technology has been proposed in which such an atomizingunit is used for a flavor inhaler (for example, Patent Document 3).

CITATION LIST Patent Literature

PTL 1: Japanese Patent Application Publication No. 2012-24646

PTL 2: Japanese Patent Application Publication (Translation of PCTApplication) No. 2016-513992

PTL3: US Patent No. 2017/0280771

SUMMARY OF INVENTION

A first feature is an inhaler, and the gist thereof is that the inhalercomprises a first liquid storage unit; a second liquid storage unit; anatomizing unit which comprises a piezoelectric element substrate havingan IDT constructed by use of a pair of interlocking comb-shaped metallicelectrodes and is constructed to atomize liquid by a surface acousticwave generated by applying a high-frequency voltage to the pair ofinterlocking comb-shaped metallic electrodes; and a mouthpiece forguiding aerosol which is generated by atomizing the liquid in theatomizing unit; wherein the atomizing unit is constructed to atomizefirst liquid supplied from the first liquid storage unit and secondliquid supplied from the second liquid storage unit, respectively.

A second feature comprises the first feature, wherein the gist thereofis that the first liquid and the second liquid are different from eachother.

A third feature comprises the first feature or the second feature,wherein the gist thereof is that the first liquid comprises at leastnicotine.

A fourth feature comprises the third feature, wherein the gist thereofis that the first liquid further comprises at least one of an acid, ataste component, and a somatosensory component.

A fifth feature comprises one of the first feature to the fourthfeature, wherein the gist thereof is that the second liquid comprises aflavor component.

A sixth feature comprises the fifth feature, wherein the gist thereof isthat the flavor component comprises at least one of menthol, limonene,citral, linalool, vanillin, carvone, and glycosides of these.

A seventh feature comprises the fifth feature or the sixth feature,wherein the gist thereof is that the second liquid further comprises atleast one of a taste component, a somatosensory component, anemulsifier, glycerin, propylene glycol, and ethanol.

A eighth feature comprises one of the first feature to the seventhfeature, wherein the gist thereof is that the mouthpiece comprises afirst flow path through which first aerosol generated by atomizing thefirst liquid passes mainly, and a second flow path through which secondaerosol generated by atomizing the second liquid, passes.

A ninth feature comprises the eighth feature when it is dependent on thethird feature or the fourth feature, wherein the gist thereof is thatthe first flow path is defined by a pipe line which comprises at least apart which is curved.

A tenth feature comprises the eighth feature when it is dependent on oneof the fifth feature to the seventh feature, wherein the gist thereof isthat the second flow path is defined by an approximately straight pipeline.

An eleventh feature comprises the eighth feature when it is dependent onthe third feature or the fourth feature, wherein the gist thereof isthat the first flow path is provided with an air flow acceleratingmember which is constructed to reduce the first flow path.

A twelfth feature comprises the first feature, wherein the gist thereofis that the first flow path is provided with a trap member which isarranged in such a manner that the aerosol passed through the air flowaccelerating member collides the trap member.

A thirteenth feature comprises one of the first feature to the seventhfeature, wherein the gist thereof is that the mouthpiece comprises aflow path in which the aerosol, which is generated by atomizing thefirst liquid, swirls while the aerosol passes through the flow path.

A fourteenth feature comprises one of the first feature to thethirteenth feature, wherein the gist thereof is that the piezoelectricelement substrate comprises a front surface on which the pair ofinterlocking comb-shaped metallic electrodes is arranged; a rear surfacepositioned opposite to the front surface; and a pair of edges oppositeto each other; and the inhaler further comprises a first liquid supplierconstructed to supply the first liquid to one of the edges of thepiezoelectric element substrate, and a second liquid supplierconstructed to supply the second liquid to another of the edges of thepiezoelectric element substrate.

A fifteenth feature comprises the fourteenth feature, wherein the gistthereof is that the inhaler comprises a cover which covers the frontsurface of the piezoelectric element substrate; wherein the covercomprises a first opening part which is positioned right above the oneedge and through which the first aerosol, which is generated byatomizing the first liquid, passes, and a second opening part which ispositioned right above the other edge and through which the secondaerosol, which is generated by atomizing the second liquid, passes.

A sixteenth feature comprises the fifteenth feature, wherein the gistthereof is that the cover comprises an opening which is different fromthe first opening part and the second opening part; wherein air thatflows into the inside side of the cover from the opening passes over theIDT and flows toward the outside side of the cover from the firstopening part and the second opening part.

A seventeenth feature comprises the fifteenth feature or the sixteenthfeature, wherein the gist thereof is that the piezoelectric elementsubstrate comprises a disposition portion where the pair of interlockingcomb-shaped metallic electrodes is positioned, and the cover is arrangedin such a manner that it covers at least the part right above thedisposition portion and is not to be in contact with the front surfaceof the piezoelectric element substrate.

An eighteenth feature comprises one of the fifteenth feature to theseventeenth feature, wherein the gist thereof is that the first flowpath communicates with the first opening part, and the second flow pathcommunicates with the second opening part.

A nineteenth feature comprises one of the first feature to theeighteenth feature, wherein the gist thereof is that the inhalercomprises a trap member constructed to trap at least a part of one ofthe first aerosol generated by atomizing the first liquid and the secondaerosol generated by atomizing the second liquid.

A twentieth feature is an inhaler, and the gist thereof is that theinhaler comprises: a piezoelectric element substrate having an IDTconstructed by use of a pair of interlocking comb-shaped metallicelectrodes; a liquid supplier for supplying liquid, which is to beatomized, to a front surface of the piezoelectric element substrate onwhich the pair of interlocking comb-shaped metallic electrodes ispositioned; a sensor, which comprises at least a pair of detection partswhich are opposite to each other, for detecting liquid supplied to thefront surface of the piezoelectric element substrate; and a controllerfor controlling, based on result of detection by the sensor, the liquidsupplier in such a manner that the liquid supplier supplies a certainquantity of the liquid to the front surface of the piezoelectric elementsubstrate.

A twenty-first feature comprises twentieth feature, wherein the gistthereof is that the detection parts are positioned apart from the frontsurface of the piezoelectric element substrate.

A twenty-second feature comprises twentieth feature or the twenty-firstfeature, wherein the gist thereof is that the piezoelectric elementsubstrate comprises an edge to which the liquid from the liquid supplieris supplied; each of the detection parts comprises a convex part whichprojects toward an opposite detection part; and a distance between theedge and the convex part is 0.10 mm to 0.20 mm.

A twenty-third feature comprises the twenty-second feature, wherein thegist thereof is that the inhaler further comprises a guide wallpositioned at an edge side of the piezoelectric element substrate; and adistance between the edge and an end surface, at the edge side, of theguide wall is equal to or longer than 0.25 mm.

A twenty-fourth feature comprises the twenty-second feature or thetwenty-third feature, wherein the gist thereof is that a distancebetween the convex parts of the detection parts, which are opposite toeach other, corresponds to an overlap length of the pair of interlockingcomb-shaped metallic electrodes.

A twenty-fifth feature comprises one of the twentieth feature to thetwenty-fourth feature, wherein the gist thereof is that thepiezoelectric element substrate comprises edges that are opposite toeach other across the pair of interlocking comb-shaped metallicelectrodes, and the sensor is arranged on each of the edges that areopposite to each other.

A twenty-sixth feature comprises one of the twentieth feature to thetwenty-fifth feature, wherein the gist thereof is that the sensorcomprises one of an electric conductivity sensor, an emitter-receiversensor, and a capacitive sensor.

A twenty-seventh feature is a controller for controlling an atomizingunit, wherein the gist thereof is that the atomizing unit comprises apiezoelectric element substrate comprising an IDT comprising a pair ofinterlocking comb-shaped metallic electrodes, and a liquid supplierconfigured to supply liquid, which is to be atomized, to thepiezoelectric element substrate; wherein the piezoelectric elementsubstrate is configured to atomize the liquid by use of a surfaceacoustic wave generated by applying a high-frequency voltage to the pairof interlocking comb-shaped metallic electrodes; and the controller isconfigured to periodically change amplitude and/or a frequency of thehigh-frequency voltage applied to the pair of interlocking comb-shapedmetallic electrodes.

A twenty-eighth feature comprises the twenty-seventh feature, whereinthe gist thereof is that the controller is configured to modulate thehigh-frequency voltage applied to the pair of interlocking comb-shapedmetallic electrodes based on a sine wave, a rectangular wave, atriangular wave, or a saw tooth wave; and the modulation is amplitudemodulation and/or frequency modulation.

A twenty-ninth feature comprises the twenty-seventh feature, wherein thegist thereof is that the controller is configured to modify theamplitude of the high-frequency voltage applied to the pair ofinterlocking comb-shaped metallic electrodes to have the form of a sinewave, a rectangular wave, a triangular wave, or a saw tooth wave.

A thirtieth comprises the twenty-ninth feature, wherein the gist thereofis that the controller is configured to modify the amplitude of thehigh-frequency voltage applied to the pair of interlocking comb-shapedmetallic electrodes by providing with, in an alternating manner, aperiod during which the high-frequency voltage is applied and a periodduring which the high-frequency voltage is not applied.

A thirty-first feature comprises one of the twenty-eighth feature to thethirtieth feature, wherein the gist thereof is that a duty ratio of therectangular wave is set in such a manner that damage to thepiezoelectric element substrate due to high temperature is avoided,and/or in such a manner that generation, by atomization, of particleshaving particle sizes larger than a predetermined size is suppressed,when the high-frequency voltage is applied to the pair of interlockingcomb-shaped metallic electrodes.

A thirty-second feature comprises the twenty-eighth feature or thetwenty-ninth feature, wherein the gist thereof is that, in a singleperiod of the triangular wave, a ratio between amplitude and a length ofa period during which a change occurs in a first direction which isparallel to the amplitude and a ratio between amplitude and a length ofa period during which a change occurs in a second direction which isopposite to the first direction are set in such a manner that damage tothe piezoelectric element substrate due to high temperature is avoided,and/or in such a manner that generation, by atomization, of particleshaving particle sizes larger than a predetermined size is suppressed,when the high-frequency voltage is applied to the pair of interlockingcomb-shaped metallic electrodes.

A thirty-third feature comprises the twenty-eighth feature or thetwenty-ninth feature, wherein the gist thereof is that a ratio between alength of a single period and amplitude of the saw tooth wave is set insuch a manner that damage to the piezoelectric element substrate due tohigh temperature is avoided, and/or in such a manner that generation, byatomization, of particles having particle sizes larger than apredetermined size is suppressed, when the high-frequency voltage isapplied to the pair of interlocking comb-shaped metallic electrodes.

A thirty-fourth feature comprises one of the twenty-seventh feature tothe thirty-third feature, wherein the gist thereof is that a frequencyof the periodical changing is equal to or higher than 50 Hz and equal toor lower than 500 Hz.

A thirty fifth feature is a controller for controlling an atomizingunit, wherein the gist thereof is that the atomizing unit comprises apiezoelectric element substrate comprising an IDT comprising a pair ofinterlocking comb-shaped metallic electrodes, and a liquid supplierconfigured to supply liquid, which is to be atomized, to thepiezoelectric element substrate; wherein the piezoelectric elementsubstrate is configured to atomize the liquid by use of a surfaceacoustic wave generated by applying a high-frequency voltage to the pairof interlocking comb-shaped metallic electrodes; and the controllerperforms control to start supply of the liquid, which is to be atomized,to the piezoelectric element substrate after predetermined time haselapsed since application of the high-frequency voltage to the pair ofinterlocking comb-shaped metallic electrodes has started.

A thirty-sixth feature comprises the thirty-fifth feature, wherein thegist thereof is that a length of the predetermined time is set in such amanner that generation, by atomization, of particles having particlesizes larger than a predetermined size is suppressed.

A thirty-seventh feature comprises the thirty-fifth feature or thethirty-sixth feature, wherein the gist thereof is that the controller isconfigured to set a speed to supply the liquid, which is to be atomized,to the piezoelectric element substrate to a predetermined value, rightafter supplying is started.

A thirty-eighth feature comprises the thirty-fifth feature or thethirty-sixth feature, wherein the gist thereof is that the controller isconfigured to set a speed to supply the liquid, which is to be atomized,to the piezoelectric element substrate to zero right after supplying isstarted, and gradually increase the supply speed to a predeterminedvalue.

A thirty-ninth feature comprises the thirty-eighth feature, wherein thegist thereof is that a length of time during which the supply speedincreases from zero to the predetermined value is set in such a mannerthat generation, by atomization, of particles having particle sizeslarger than a predetermined size is suppressed.

A fortieth feature is a controller for controlling an atomizing unit,wherein the gist thereof is that the atomizing unit comprises apiezoelectric element substrate comprising an IDT comprising a pair ofinterlocking comb-shaped metallic electrodes, a liquid supplierconfigured to supply liquid, which is to be atomized, to thepiezoelectric element substrate, and a sensor for detecting a quantityof the liquid. which is to be atomized, which exists on thepiezoelectric element substrate; wherein the piezoelectric elementsubstrate is configured to atomize the liquid by use of a surfaceacoustic wave generated by applying a high-frequency voltage to the pairof interlocking comb-shaped metallic electrodes; and the controller isconfigured to control supply of the liquid, which is to be atomized, tothe piezoelectric element substrate based on the quantity of the liquidexisting on the piezoelectric element substrate.

A forty-first feature comprises the fortieth feature, wherein the gistthereof is that the controller is configured to start, at the same time,application of the high-frequency voltage to the pair of interlockingcomb-shaped metallic electrodes, and supply of the liquid, which is tobe atomized, to the piezoelectric element substrate.

A forty-second feature comprises the fortieth feature, wherein the gistthereof is that the controller is configured to start supply of theliquid, which is to be atomized, to the piezoelectric element substrate,after starting application of the high-frequency voltage to the pair ofinterlocking comb-shaped metallic electrodes.

A forty-third feature comprises one of the fortieth feature to theforty-second feature, wherein the gist thereof is that the controller isconfigured to control supply of the liquid, which is to be atomized, tothe piezoelectric element substrate in such a manner that a quantity,that is in a first predetermined range of quantities, of the liquid,which is to be atomized, exists on the piezoelectric element substrate,before application of the high-frequency voltage to the pair ofinterlocking comb-shaped metallic electrodes is started.

A forty-fourth feature comprises the forty-third feature, wherein thegist thereof is that the first predetermined range of quantities is setin such a manner that generation, by atomization, of particles havingparticle sizes larger than a predetermined size is suppressed.

A forty-fifth feature comprises one of the fortieth feature to theforty-fourth feature, wherein the gist thereof is that controller isconfigured to control supply of the liquid, which is to be atomized, tothe piezoelectric element substrate in such a manner that the speed ofsupply of the liquid, which is to be atomized, to the piezoelectricelement substrate is made to have a predetermined value or predeterminedchange, after application of the high-frequency voltage to the pair ofinterlocking comb-shaped metallic electrodes is started.

A forty-sixth feature comprises one of the fortieth feature to theforty-fifth feature, wherein the gist thereof is that the controller isconfigured to stop supply of the liquid, which is to be atomized, to thepiezoelectric element substrate, in the case that the quantity of theliquid, which is to be atomized, existing on the piezoelectric elementsubstrate is equal to or above an upper limit in a second predeterminedrange of quantities, when supplying the liquid, which is to be atomized,to the piezoelectric element substrate; and the upper limit and a lowerlimit of the second predetermined range of quantities are equal to orlarger than an upper limit and a lower limit of the first predeterminedrange of quantities, respectively.

A forty-seventh feature comprises the forty-sixth feature, wherein thegist thereof is that the controller is configured to restart supply ofthe liquid, which is to be atomized, to the piezoelectric elementsubstrate, in the case that the quantity of the liquid, which is to beatomized, existing on the piezoelectric element substrate is less thanthe lower limit of the second predetermined range of quantities, whensupply of the liquid, which is to be atomized, to the piezoelectricelement substrate is being stopped.

A forty-eighth feature comprises the forty-sixth feature or theforty-seventh feature, wherein the gist thereof is that the secondpredetermined range of quantities is set in such a manner thatgeneration, by atomization, of particles having particle sizes largerthan a predetermined size is suppressed.

A forty-ninth feature comprises a program, wherein the gist thereof isthat the program makes a processor to function as at least a part of thecontroller recited in one of the twenty-seventh feature to theforty-eighth feature.

A fiftieth feature is an inhaler, and the gist thereof is that theinhaler comprises an atomizing unit which comprises a piezoelectricelement substrate having a first IDT consisting of a pair ofinterlocking comb-shaped electrodes and is configured to atomize liquidby a surface acoustic wave generated by applying a high-frequencyvoltage to the pair of interlocking comb-shaped electrodes, and acontroller configured to monitor a resonant frequency of the pair ofinterlocking comb-shaped electrodes and apply a voltage to the pair ofinterlocking comb-shaped electrodes at a frequency determined based onthe monitored resonant frequency.

A fifty first feature comprises the fiftieth feature, wherein the gistthereof is that the controller is configured to, when monitoring theresonant frequency, apply a voltage to the pair of interlockingcomb-shaped electrodes at a frequency selected from multiple differentfrequencies and determine as the resonant frequency, a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes whenpower reflected from the pair of interlocking comb-shaped electrodes isthe lowest.

A fifty second feature comprises the fifty first feature, wherein thegist thereof is that the controller is configured to detect first powerreflected from the pair of interlocking comb-shaped electrodes when avoltage is applied to the pair of interlocking comb-shaped electrodes ata first frequency, detect second power reflected from the pair ofinterlocking comb-shaped electrodes when a voltage is applied to thepair of interlocking comb-shaped electrodes at a second frequencyseparated from the first frequency by a first value, and apply a voltageto the pair of interlocking comb-shaped electrodes at a third frequencyseparated from the second frequency by a second value that is smallerthan the first value when the second power is lower than the firstpower.

A fifty third feature comprises the fifty first feature, wherein thegist thereof is that the controller is configured to monitor reflectedpower from the pair of interlocking comb-shaped electrodes whilediscretely increasing or decreasing a frequency of a voltage applied tothe pair of interlocking comb-shaped electrodes, end a scan when thetrend of the value indicating reflected power shifts from a decreasingtrend to an increasing trend, and determine as the resonant frequency, afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes when the reflected power becomes the lowest.

A fifty fourth feature comprises the fifty first feature, wherein thegist thereof is that the controller is configured to monitor reflectedpower from the pair of interlocking comb-shaped electrodes whilediscretely increasing a frequency of a voltage applied to the pair ofinterlocking comb-shaped electrodes, reduce the range of variation in afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes and discretely decrease the frequency when the trend of thevalue indicating the reflected power shifts from a decreasing trend toan increasing trend.

A fifty fifth feature comprises the fifty first feature, wherein thegist thereof is that the controller is configured to monitor reflectedpower from the pair of interlocking comb-shaped electrodes whilediscretely decreasing a frequency of a voltage applied to the pair ofinterlocking comb-shaped electrodes, reduce the range of variation in afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes and discretely increase the frequency when the trend of thevalue indicating the reflected power shifts from a decreasing trend toan increasing trend.

A fifty sixth feature comprises the fifty first feature, wherein thegist thereof is that the controller is configured to determine aresonant frequency monitored before the start of atomization of liquidby the atomizing unit, a resonant frequency estimated from thetemperature of the piezoelectric element substrate or a frequencyclosest to the resonant frequency at the time of the previous inhalationas a frequency to be selected first from the multiple differentfrequencies.

A fifty seventh feature comprises the fiftieth feature, wherein the gistthereof is that the inhaler further comprises a second IDT located onthe piezoelectric element substrate and configured to generate a voltagein response to the surface acoustic wave and the controller isconfigured to, when monitoring the resonant frequency, apply a voltageto the pair of interlocking comb-shaped electrodes at a frequencyselected from multiple different frequencies and determine as theresonant frequency, a frequency of a voltage applied to the pair ofinterlocking comb-shaped electrodes when a voltage arising at the secondIDT is the highest.

A fifty eighth feature comprises the fifty seventh feature, wherein thegist thereof is that the controller is configured to detect a firstvoltage arising at the second IDT when a voltage is applied to the pairof interlocking comb-shaped electrodes at a first frequency, detect asecond voltage arising at the second IDT when applying a voltage to thepair of interlocking comb-shaped electrodes at a second frequencyseparated from the first frequency by a first value, and apply a voltageto the pair of interlocking comb-shaped electrodes at a third frequencyseparated from the second frequency by a second value that is smallerthan the first value when the second voltage is higher than the firstvoltage.

A fifty ninth feature comprises the fifty seventh feature, wherein thegist thereof is that the controller is configured to monitor a voltagearising at the second IDT while discretely increasing or decreasing afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes, end a scan when the trend of the value of the voltagearising at the second IDT shifts from an increasing trend to adecreasing trend, and determine as the resonant frequency, a frequencyof a voltage applied to the pair of interlocking comb-shaped electrodeswhen the voltage becomes the highest.

A sixtieth feature comprises the fifty seventh feature, wherein the gistthereof is that the controller is configured to monitor a voltagearising at the second IDT while discretely increasing a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes,reduce the range of variation in a frequency of a voltage applied to thepair of interlocking comb-shaped electrodes and discretely decrease thefrequency when the trend of the value of the voltage arising at thesecond IDT shifts from an increasing trend to a decreasing trend.

A sixty first feature comprises the fifty seventh feature, wherein thegist thereof is that the controller is configured to monitor a voltagearising at the second IDT while discretely decreasing a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes,reduce the range of variation in a frequency of a voltage applied to thepair of interlocking comb-shaped electrodes and discretely increase thefrequency when the trend of the value of the voltage arising at thesecond IDT shifts from an increasing trend to a decreasing trend.

A sixty second feature comprises the fifty seventh feature, wherein thegist thereof is that the controller is configured to determine aresonant frequency monitored before the start of atomization of theliquid by the atomizing unit, a resonant frequency estimated from thetemperature of the piezoelectric element substrate or a frequencyclosest to the resonant frequency at the time of the previous inhalationas a frequency to be selected first from the multiple differentfrequencies.

A sixty third feature comprises any one of the fiftieth to sixty secondfeatures, wherein the gist thereof is that the controller is configuredto monitor the resonant frequency before the start or after the end ofatomization of the liquid by the atomizing unit.

A sixty fourth feature comprises any one of the fiftieth to sixty secondfeatures, wherein the gist thereof is that the controller is configuredto monitor the resonant frequency after detecting a request to atomizethe liquid.

A sixty fifth feature comprises any one of the fiftieth to sixty secondfeatures, wherein the gist thereof is that the controller is configuredto apply a voltage to the pair of interlocking comb-shaped electrodes ata frequency determined based on the monitored resonant frequency duringatomization of the liquid by the atomizing unit.

A sixty sixth feature comprises the sixty third feature, wherein thegist thereof is that the controller is configured to determine a rangeof frequencies including the monitored resonant frequency and control afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes in such a manner as to vary within the determined range offrequencies during atomization of the liquid by the atomizing unit.

The sixty seventh feature comprises the sixty sixth feature, wherein thegist thereof is that the inhaler further comprises a memory unit forstoring a correspondence between a resonant frequency and a frequencyrange and the controller is configured to determine the frequency rangebased on the monitored resonant frequency and the correspondence.

The sixty eighth feature comprises any one of the fiftieth to sixtysecond features, wherein the gist thereof is that the resonant frequencyis monitored during atomization of the liquid by the atomizing unit.

The sixty ninth feature comprises the sixth eighth feature, wherein thegist thereof is that the controller is configured to control a frequencyof a voltage applied to the pair of interlocking comb-shaped electrodesin such a manner as to vary within a predetermined range and adjust thepredetermined range in such a manner as to include the monitoredresonant frequency, during atomization of the liquid by the atomizingunit.

The seventieth feature comprises the sixty eighth feature, wherein thegist thereof is that the controller is configured to control a frequencyof a voltage applied to the pair of interlocking comb-shaped electrodesand determine the monitored resonant frequency as a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes atthe time of the next inhalation, during atomization of the liquid by theatomizing unit.

The seventy first feature comprises any one of fiftieth to sixty secondfeatures, wherein the gist thereof is that the inhaler further comprisesa temperature sensor for detecting a temperature of the piezoelectricelement substrate, wherein the controller is configured to obtain thetemperature detected by the temperature sensor and determine a frequencyof a voltage applied to the pair of interlocking comb-shaped electrodesbased on the detected temperature, during atomization of the liquid bythe atomizing unit.

The seventy second feature comprises the seventy first feature, whereinthe gist thereof is that the controller is configured to predict avariation in a resonant frequency during atomization of the liquid bythe atomizing unit based on the detected temperature and determine afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes based on the predicted variation in the resonant frequency.

The seventy third feature comprises the seventy second feature, whereinthe gist thereof is that the inhaler further comprises a memory unit forstoring a correspondence between a temperature and a resonant frequencyof the pair of interlocking comb-shaped electrodes, wherein thecontroller is configured to predict a variation in the resonantfrequency based on the detected temperature and the correspondence.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a flavor inhaler 1 according to anembodiment.

FIG. 2 is a diagram illustrating an atomizing unit 100 according to theembodiment.

FIG. 3 is a diagram illustrating a planar view of a SAW module 30 viewedfrom a front surface side of a piezoelectric element substrate 31.

FIG. 4 is a diagram illustrating a cross-section of the SAW module 30.

FIG. 5 is a diagram for describing a mechanism of generating an aerosol.

FIG. 6 is a diagram for describing a penetrated aperture 34 according toa first modification.

FIG. 7 is a diagram for describing a separation wall 37 according to asecond modification.

FIG. 8 is a diagram for describing the separation wall 37 according tothe second modification.

FIG. 9 is a diagram for describing a hydrophilic layer 38 according to athird modification.

FIG. 10 shows photographs of a result of a first experiment.

FIG. 11 is a table showing a result of a second experiment.

FIG. 12 is a graph showing a result of a third experiment.

FIG. 13 is a diagram for describing a fifth modification.

FIG. 14 is a diagram for describing a sixth modification.

FIG. 15 is a diagram for describing the sixth modification.

FIG. 16 is a diagram for describing a seventh modification.

FIG. 17 is a diagram for describing the seventh modification.

FIG. 18 is a diagram for describing an eighth modification.

FIG. 19 is a diagram for describing the eighth modification.

FIG. 20 is a diagram for describing the eighth modification.

FIG. 21 is a diagram for describing a ninth modification.

FIG. 22 is a diagram for describing the ninth modification.

FIG. 23 is a diagram for describing the ninth modification.

FIG. 24 is a diagram for describing the ninth modification.

FIG. 25 is a diagram for describing the ninth modification.

FIG. 26 is a diagram for describing a tenth modification.

FIG. 27 is a diagram for describing an eleventh modification.

FIG. 28 is a diagram for describing a twelfth modification.

FIG. 29 is a diagram for describing a thirteenth modification.

FIG. 30 is a diagram for describing a fourteenth modification.

FIG. 31 is a diagram for describing the fourteenth modification.

FIG. 32 is a diagram for describing the fourteenth modification.

FIG. 33 is a diagram for describing the fourteenth modification.

FIG. 34 is a diagram for describing a fifteenth modification.

FIG. 35 is a diagram for describing a sixteenth modification.

FIG. 36 is a diagram for describing the sixteenth modification.

FIG. 37 is a diagram for describing a seventeenth modification.

FIG. 38 is a diagram for describing an eighteenth modification.

FIG. 39 is a diagram for describing a nineteenth modification.

FIG. 40 is a diagram for describing the nineteenth modification.

FIG. 41 is a diagram for describing the nineteenth modification.

FIG. 42 is a diagram for describing a twentieth modification.

FIG. 43 is a diagram for describing the twentieth modification.

FIG. 44 is a diagram for describing the twentieth modification.

FIG. 45 is a diagram for describing a twenty second modification.

FIG. 46 is a diagram for describing a twenty third modification.

FIG. 47 is a diagram for describing the twenty third modification.

FIG. 48 is a diagram for describing a result of an experiment.

FIG. 49 is a perspective view showing an example of an exterior of theunit which is that from which the sensor, the controller, and the powersource of the flavor inhaler 1 shown in FIG. 1 have been removed.

FIG. 50 is a longitudinal section of the unit shown in FIG. 49.

FIG. 51 is an exploded perspective view of the unit shown in FIG. 49.

FIG. 52 is an exploded perspective view of the atomizing unit from whichthe first cover and the second cover have been removed.

FIG. 53 is a cross-section view of the atomizing unit.

FIG. 54 is a side cross-section view of the mouthpiece.

FIG. 55 is a side cross-section view showing another example of themouthpiece.

FIG. 56 is a perspective view showing a further example of themouthpiece.

FIG. 57 is a schematic drawing of the mouthpiece wherein cross sectionsof the separation part and the air outlet shown in FIG. 56 are shown.

FIG. 58 is a side cross-section view showing a still further example ofthe mouthpiece.

FIG. 59 is a schematic side view showing the flow of air passing throughthe mouthpiece shown in FIG. 58.

FIG. 60 is a side cross-section view showing a still further example ofthe mouthpiece.

FIG. 61 is a schematic side view showing the flow of air passing throughthe mouthpiece shown in FIG. 60.

FIG. 62 is a graph showing a result of measurement of diameterdistribution with respect to aerosol in experiment 1.

FIG. 63 is a graph showing discomfort in a throat.

FIG. 64 is an enlarged view of a part extracted from the atomizing unitshown in FIG. 52.

FIG. 65 is a graph showing relationship between the spaces C2 shown inFIG. 64 and the atomizing amounts.

FIG. 66 is a graph showing relationship between the spaces L1 shown inFIG. 64 and the atomizing amounts.

FIG. 67 is figure for explaining twenty-sixth modification A.

FIG. 68 is figure for explaining twenty-sixth modification A.

FIG. 69 is figure for explaining twenty-sixth modification D.

FIG. 70 is figure for explaining twenty-sixth modification D.

FIG. 71 is figure for explaining twenty-sixth modification D.

FIG. 72 is figure for explaining twenty-sixth modification D.

FIG. 73 is figure for explaining twenty-sixth modification E.

FIG. 74 is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 75 illustrates an example of a control circuit of the inhaler.

FIG. 76 is a flow chart illustrating a specific example of a processperformed at step 4004 in FIG. 74.

FIG. 77 shows graphs for explaining an example of a method ofdetermining a resonant frequency during the process illustrated in FIG.76.

FIG. 78A illustrates an example of a configuration of the inhaleraccording to the twenty seventh modification for determining a resonantfrequency by a method that differs from the method explained in FIG. 77.

FIG. 78B illustrates an example of the arrangement of the first andsecond IDTs.

FIG. 78C illustrates an example of the arrangement of the first andsecond IDTs.

FIG. 78D illustrates an example of the arrangement of the first andsecond IDTs.

FIG. 79 is a flow chart illustrating a specific example of a processperformed at step 4004 in FIG. 74.

FIG. 80A is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 80B is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 80C is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 81A is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 81B is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification

FIG. 81C is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 82 is a flow chart illustrating a method of operating the inhaleraccording to the twenty seventh modification.

FIG. 83 is a flow chart illustrating a specific example of a processperformed at step 4814.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described. Inthe following description of the drawings, the same or similar parts aredenoted by the same or similar reference numerals. It is noted that thedrawings are schematic, and the ratios of dimensions and the like may bedifferent from the actual ones.

Therefore, specific dimensions and the like should be determined byreferring to the following description. Of course, the drawings mayinclude the parts with different dimensions and ratios.

[Overview of Disclosure]

As described in the background art, technology has been proposed inwhich an atomizing unit using a piezoelectric element substrate is usedfor a flavor inhaler. As a result of extensive studies, the inventorsfound that various means need to be devised if using a piezoelectricelement substrate in an atomizing unit to be used for the flavorinhaler.

An atomizing unit according to the overview of disclosure comprises: apiezoelectric element substrate having an interdigital transducer madeof a pair of interlocking comb-shaped metallic electrodes; and a liquidsupplier configured to supply liquid to be aerosolized to thepiezoelectric element substrate. The piezoelectric element substrate isconfigured to atomize the liquid by use of a surface acoustic wavegenerated by applying a voltage to the pair of interlocking comb-shapedmetallic electrodes at a high frequency (resonant frequency). Thepiezoelectric element substrate has a certain number of the pair ofinterlocking comb-shaped metallic electrodes, the certain number beingdetermined based on a desired aerosol atomized by use of the surfaceacoustic wave.

According to the overview of the disclosure, the number of pair ofinterlocking comb-shaped metallic electrodes is determined based on adesired aerosol. Therefore, as the atomizing unit having the limitedpower that can be supplied to the pair of interlocking comb-shapedmetallic electrodes, it is possible to provide an appropriate atomizingunit by improving atomizing efficiency of the liquid.

Embodiment

(Flavor Inhaler)

A flavor inhaler according to an embodiment will be described below.FIG. 1 is a diagram illustrating a flavor inhaler 1 according to theembodiment.

As illustrated in FIG. 1, the flavor inhaler 1 has an atomizing unit100, a liquid storage unit 200, a sensor 300, a controller 400, and apower source 500. The flavor inhaler 1 has a housing 1X configured tohouse the atomizing unit 100, the liquid storage unit 200, the sensor300, the controller 400, and the power source 500. The housing 1X mayhave a rectangular box shape as illustrated in FIG. 1, or may have acylindrical shape. The flavor inhaler 1 has a chamber 1C communicatingfrom an inlet 1A to an outlet 1B. The outlet 1B may be provided with amouthpiece 1D. The mouthpiece 1D may be a continuous body with thehousing 1X, or may be a separate body from the housing 1X. Themouthpiece 1D may have a filter.

The atomizing unit 100 atomizes a liquid to be aerosolized supplied fromthe liquid storage unit 200. The atomizing unit 100 uses a surfaceacoustic wave (SAW) to atomize the liquid. The atomizing unit 100 may bea cartridge configured to be detachable. Details of the atomizing unit100 will be given later.

The liquid storage unit 200 houses the liquid. The liquid storage unit200 may be a cartridge configured to be detachable. The liquid storageunit 200 may be integrally formed with the atomizing unit 100. Theliquid may include solvents such as water, glycerin, propylene glycol,and ethanol. The liquid may include solutes (flavor components)contributing to at least any one of a fragrance and a taste. The flavorcomponent may include a volatile component and a non-volatile component.It may be sufficient that the volatile component is a componentgenerally used as a flavor. The volatile component may be aplant-derived component or a synthetic component. Examples of thevolatile component include menthol, limonene, linalool, vanillin,tobacco extracts, and the like. The non-volatile component may be acomponent contributing to the sense of taste. Examples of thenon-volatile component include sugars such as glucose, fructose, sucroseand lactose; bitter substance such as tannin, catechin, and naringin,acids such as malic acid and citric acid, and salts. The liquid may bein an emulsified state by an emulsifier, or may be in a suspended stateby a dispersant. The liquid may include an ionic substance and awater-soluble flavor that is insoluble in glycerin and propylene glycoland soluble in water.

If the liquid storage unit 200 is a cartridge and a SAW module describedbelow has two or more penetrated apertures, the liquid may be suppliedto the two or more penetrated apertures from one cartridge, or theliquid may be supplied to the two or more penetrated aperturesindividually from two or more cartridges. If two or more cartridges areprovided, each cartridge may store liquid of a different kind. Forexample, a first cartridge may store a volatile component and a secondcartridge may store a non-volatile component.

If the liquid storage unit 200 is a cartridge, the cartridge may includethe above-described mouthpiece 1D as a continuous body. According tosuch a configuration, the mouthpiece 1D is also replaced when thecartridge is replaced, and thus, the mouthpiece 1D is hygienicallymaintained.

If the liquid storage unit 200 is a cartridge, the cartridge may be adisposable type, or may be a refillable type. The refillable type is atype that a user refills the cartridge with liquid of choice.

The sensor 300 detects a puff action of a user. For example, the sensor300 detects a flow of gas passing through the chamber 1C. For example,the sensor 300 is a flow rate sensor. The flow rate sensor includes anorifice disposed within the chamber 1C. The flow rate sensor monitors apressure difference between an upstream of the orifice and a downstreamof the orifice, and detects an air flow by the monitored pressuredifference.

The controller 400 is configured of a processor, a memory, and the like,and controls each configuration provided to the flavor inhaler 1. Thecontroller 400 may be an article configured to be detachable. Forexample, the controller 400 specifies a start of a puff action by adetection result of the sensor 300. The controller 400 may start anatomization action of the atomizing unit 100, in response to the startof the puff action. The controller 400 may specify a stop of the puffaction by the detection result of the sensor 300. The controller 400 maystop the atomization action of the atomizing unit 100, in response tothe stop of the puff action. If a certain period has passed from thestart of the puff action, the controller 400 may stop the atomizationaction of the atomizing unit 100.

In the embodiment, the controller 400 may include a voltage andfrequency control circuit configured to control the SAW module describedbelow. A voltage and frequency adjustment circuit controls, as theatomization action of the atomizing unit 100, a frequency and magnitudeof power (for example, AC voltage) supplied to a SAW module 30. However,as described below, the voltage and frequency adjustment circuit may beprovided to a drive circuit board 20.

The power source 500 supplies power for driving the flavor inhaler 1.The power source 500 may be a primary battery such as a manganesebattery, an alkaline battery, an oxyride battery, a nickel battery, anickel manganese battery, and a lithium battery, or may be a secondarybattery such as a nickel-cadmium battery, a nickel-metal hydridebattery, and a lithium battery. The power source 500 may be an articleconfigured to be detachable.

(Atomizing Unit)

An atomizing unit according to the embodiment will be described below.FIG. 2 is a diagram illustrating the atomizing unit 100 according to theembodiment.

As illustrated in FIG. 2, the atomizing unit 100 has a housing 10, thedrive circuit board 20, the SAW module 30, a ceiling plate 40, and a topcover 50.

The housing 10 houses the drive circuit board 20, the SAW module 30, andthe ceiling plate 40. The housing 10 may house a housing body configuredto house the liquid to be aerosolized, or may house a liquid supplier(for example, a syringe pump) configured to supply the liquid to the SAWmodule 30.

The drive circuit board 20 has a drive circuit configured to drive theSAW module 30. The drive circuit board 20 may be considered to include apart of the above-described controller 400 (for example, the voltage andfrequency control circuit). Alternatively, the drive circuit board 20may be considered to be a part of the controller 400. For example, thedrive circuit uses the power supplied from the power source 500 to drivethe SAW module 30. The drive circuit controls the frequency and themagnitude of the power (for example, AC voltage) supplied to the SAWmodule 30. The drive circuit may control an amount of the liquidsupplied to the SAW module 30.

As described below, the SAW module 30 has a piezoelectric elementsubstrate having interdigital transducer made of at least one pair ofinterlocking comb-shaped metallic electrodes. Details of the SAW module30 will be described later (see FIG. 3 and FIG. 4).

The ceiling plate 40 is a plate-like member disposed on the drivecircuit board 20 and the SAW module 30. The drive circuit board 20 andthe SAW module 30 are disposed between the housing 10 and the ceilingplate 40. The ceiling plate 40 has an opening 41 exposing at least thepiezoelectric element substrate. For example, the ceiling plate 40 isconfigured by stainless steel.

The top cover 50 is disposed on the ceiling plate 40. The top cover 50has an inlet 51 and an outlet 52 and has an air flow path extending fromthe inlet 51 to the outlet 52. The aerosol is led out from the SAWmodule 30 to the outlet 52 by an airstream from inlet 51 to outlet 52.The top cover 50 may have an O ring 53 configured to improveairtightness of the air flow path. For example, the top cover 50 isconfigured by resins having heat resistance such as polycarbonates, andthe 0 ring 53 may be configured by resins having elasticity such assilicon. A position of the outlet 52 may be any position and the outlet52 may be provided immediately above the opening 41 of the ceiling plate40. According to such a configuration, it is possible to efficientlylead the aerosol generated toward a direction immediately above the SAWmodule 30 and an aerosol flow path can be shortened. The outlet 52 mayhave a filter.

(Saw Module)

A SAW module according to the embodiment will be described below. FIG. 3is a diagram illustrating a planar view of the SAW module 30 viewed fromthe front surface side of a piezoelectric element substrate 31. FIG. 4is a diagram illustrating a cross-section of the SAW module 30.

As illustrated in FIG. 3 and FIG. 4, the SAW module 30 has thepiezoelectric element substrate 31, an electrode (a main body portion 32and an interdigital transducer made of the pairs of interlockingcomb-shaped metallic electrodes 33), a penetrated aperture 34, and aheat sink structure 35. The piezoelectric element substrate 31 isconfigured to atomize the liquid by use of a SAW generated by applying avoltage to the pairs of interlocking comb-shaped metallic electrodes 33at a high frequency (resonant frequency).

The piezoelectric element substrate 31 includes a front surface 31F onwhich the main body portion 32 and the pairs of interlocking comb-shapedmetallic electrodes 33 are disposed and a rear surface 31B provided onan opposite side of the front surface 31F. The piezoelectric elementsubstrate 31 includes a piezoelectric body configured to expand andcontract as a result of applying the voltage thereto. A portion of thepiezoelectric element substrate 31 where the pairs of interlockingcomb-shaped metallic electrodes 33 are disposed may be referred to as adisposition portion 30A. It may be sufficient that the piezoelectricbody configures at least the front surface 31F. As the piezoelectricbody, a known piezoelectric body configured by ceramics such as quartz,barium titanate, and lithium niobate can be used.

The main body portion 32 is electrically connected to the power source500. The main body portion 32 includes a first main body portion 32Aintegrally formed with a first electrode 33A that is one of the pairs ofinterlocking comb-shaped metallic electrodes 33, and a second main bodyportion 32B integrally formed with a second electrode 33B that is theother one of the pairs of interlocking comb-shaped metallic electrodes33. The first main body portion 32A and the second main body portion 32Bare disposed, with the disposition portion 30A being sandwichedtherebetween, in an orthogonal direction B to a travel direction A ofthe SAW. The power output from a battery is supplied to the pairs ofinterlocking comb-shaped metallic electrodes 33 through the main bodyportion 32.

The pairs of interlocking comb-shaped metallic electrodes 33 include thefirst electrode 33A and the second electrode 33B. The first electrode33A and the second electrode 33B are alternately disposed in the traveldirection A of the SAW. The first electrode 33A has a shape extendingalong the orthogonal direction B from the first main body portion 32A.The second electrode 33B has a shape extending along the orthogonaldirection B from the second main body portion 32B. For example, thepairs of interlocking comb-shaped metallic electrodes 33 are configuredby gold plated metal and the like.

The penetrated aperture 34 is an aperture penetrating the piezoelectricelement substrate 31 from the rear surface 31B to the front surface 31F.The penetrated aperture 34 forms a flow path leading the liquid from therear surface 31B to the front surface 31F. The penetrated aperture 34has, in a planar view viewed from a side of the front surface 31F, amaximum width W_(MAX) in the travel direction A of the SAW and a maximumlength L_(MAX) in the orthogonal direction B. The maximum length L_(MAX)is greater than the maximum width W_(MAX). In other words, thepenetrated aperture 34 has a shape longer in the orthogonal direction B(for example, an elliptical shape or a rectangular shape). If thepenetrated aperture 34 is an elliptical shape or a rectangular shape, itmay be sufficient that a longitudinal axis of the penetrated aperture 34extends along the orthogonal direction B. “Extending along theorthogonal direction B” may mean to have an inclination in which thelongitudinal axis of the penetrated aperture 34 is equal to or less than45° with respect to the orthogonal direction B. It is preferable thatthe maximum length L_(MAX) is greater than a length of the dispositionportion 30A in the orthogonal direction B (for example, overlappingportion of the first electrode 33A and the second electrode 33B). Asillustrated in FIG. 3, it is preferable that the penetrated aperture 34includes at least two penetrated apertures that sandwich the pairs ofinterlocking comb-shaped metallic electrodes 33. According to such aconfiguration, it increases an interaction of SAW and liquid andincreases the amount of liquid atomized for the same power.

The heat sink structure 35 is a structure configured to conduct away theheat generated by a reflection of the surface acoustic wave on an edgeof the piezoelectric element substrate 31. The heat sink structure 35includes at least any one of a heat conductive layer and a Peltierelement, the heat conductive layer being configured by a material havinga thermal conductivity higher than a thermal conductivity of thepiezoelectric element substrate 31. The heat sink structure 35 has apenetrated aperture 35A continuous to the penetrated aperture 34. Thepenetrated aperture 35A is an aperture through which the liquid is ledto the front surface 31F of the piezoelectric element substrate 31. Inan example illustrated in FIG. 4, the heat sink structure 35 is a heatconductive layer disposed on the rear surface 31B of the piezoelectricelement substrate 31. However, the embodiment is not limited thereto.For example, the heat sink structure 35 may only need to be in contactwith the piezoelectric element substrate 31 and may be disposed on thefront surface 31F of the piezoelectric element substrate 31. The heatsink structure 35 may be a Peltier element. The heat sink structure 35may include both the heat conductive layer and the Peltier element. Forexample, as the heat conductive layer, metals such as aluminum, copper,and iron may be used, and carbon, Aluminum nitride, and ceramics mayalso be used. For example, the Peltier element may be stuck to thepiezoelectric element substrate 31 by an adhesive (a grease, an epoxyresin, a metal paste). It is preferable that the thermal conductivity ofthe adhesive is higher than 0.1 W/m/K. Further, it is preferable thatthe thermal conductivity of the adhesive is higher than 0.5 W/m/K. Thethinner adhesive would be preferable, and the thin adhesive may beavailable by a screen printing.

As illustrated in FIG. 4, a liquid supplier 60 is provided on a side ofthe rear surface 31B of the piezoelectric element substrate 31, theliquid supplier 60 is configured to supply the liquid to thepiezoelectric element substrate 31. The liquid supplier 60 supplies theliquid to the front surface 31F of the piezoelectric element substrate31 through the penetrated aperture 34 and the penetrated aperture 35A.

For example, the liquid supplier 60 is a syringe pump. In such a case,the penetrated aperture 34 and the penetrated aperture 35A configure aflow path of the liquid. The syringe pump may be manually operated orelectrically operated.

In FIG. 3, a case is exemplified where the liquid supplier 60 is asyringe pump; however, the embodiment is not limited to this. Forexample, the liquid supplier 60 may be a member configured to supply theliquid by a capillary phenomenon. In such a case, the liquid supplier 60includes a capillary member through which the liquid is suctioned up andthe penetrated aperture 34 and the penetrated aperture 35A configure anaperture through which the capillary member is passed. A first end ofthe capillary member at least reaches the liquid storage unit 200 and asecond end of the capillary member reaches the SAW module 30. In across-section of the penetrated aperture 34 and the penetrated aperture35A, the capillary member is disposed on at least a part of thecross-section. The capillary member may be configured by at least anyone of a naturally derived fiber material, a plant-derived fibermaterial, and a synthetic fiber material. For example, the naturallyderived fiber material may be at least any one of a dried plant, acut-up dried plant, cut-up leaf tobacco, a dried fruit, a cut-up driedfruit, a dried vegetable, and a cut-up dried vegetable. For example, theplant-derived fiber material may be at least any one of an absorbentcotton and a linen fiber. The capillary member may be a cut-up driedplant formed in a sheet shape, such as a cut-up filter paper and acut-up tobacco sheet.

Further, the liquid supplier 60 may be a combination of the syringe pumpand the capillary member. If a remaining amount of the liquid stored inthe liquid storage unit 200 is equal to or more than a threshold value,the liquid may be supplied by the capillary member and if the remainingamount of the liquid is less than the threshold value, the liquid may besupplied by the syringe pump. The controller 400 may determine, based ona predetermined reference, whether to use either the syringe pump or thecapillary member.

If the liquid storage unit 200 is a cartridge, the liquid supplier 60may automatically supply the liquid to the SAW module 30 in response toan attachment of the cartridge. If a power source switch configured todrive the flavor inhaler 1 is provided, the liquid supplier 60 mayautomatically supply the liquid to the SAW module 30 in response to theturning on of the power source.

As illustrated in FIG. 4, the SAW module 30 may include a coating layer36. The coating layer 36 may entirely cover the piezoelectric elementsubstrate 31, or may partially cover the piezoelectric element substrate31. The coating layer 36 may be provided on an inner surface of thepenetrated aperture 34. According to such a configuration, it ispossible to prevent the liquid from coming in contact with thepiezoelectric element substrate 31. Further, by conformably depositingthe coating material, the coating layer 36 may be provided on an innersurface of the penetrated aperture 35A, in addition to the inner surfaceof the penetrated aperture 34. According to such a configuration, it ispossible to further prevent the liquid from coming in contact with thepiezoelectric element substrate 31.

It may be sufficient that the coating layer 36 is configured by amaterial suppressing denaturation of the piezoelectric element substrate31 caused due to adherence or the like of the liquid. For example, thecoating layer 36 may be configured by polymeric materials such aspolypropylene and polyethylene. The coating layer 36 may be configuredby a material such as metal, carbon, Teflon (trademark), glass,Parylene, Silicon dioxide, and Titanium dioxide, or a ceramic materialsuch as Silicon nitride, Silicon oxynitride, and Alumina oxide.

Under such premise, the piezoelectric element substrate 31 has a certainnumber of pairs of interlocking comb-shaped metallic electrodes 33, thecertain number being determined based on a desired aerosol atomized byuse of the SAW. Specifically, the number of pairs of interlockingcomb-shaped metallic electrodes 33 is determined based on atomizingefficiency of the aerosol atomized by use of the SAW. The interval ofelectrodes adjacent to each other included in the pairs of interlockingcomb-shaped metallic electrodes 33 and the width of the electrodes inthe travel direction are determined in accordance with a frequency setbased on a desired particle size of the aerosol atomized by use of theSAW.

Here, the desired aerosol is an aerosol including an aerosol having thedesired particle size as a peak of the number concentration. Theatomizing efficiency is a degree of the number concentration of theaerosol in a case where the power supplied to the pairs of interlockingcomb-shaped metallic electrodes 33 is constant. The number concentrationis the number of aerosol particles included per unit volume. Forexample, the number concentration of sub-micron droplets is equal to ormore than 10⁸/cm³.

In the embodiment, the power supplied to the pairs of interlockingcomb-shaped metallic electrodes 33 is provided by a battery included inthe flavor inhaler having the atomizing unit 100. Under such anenvironment, it is preferable that the power supplied to the pairs ofinterlocking comb-shaped metallic electrodes 33 is equal to or more than3 W. When the power is equal to or more than 3 W, the atomization of theliquid appropriately occurs. On the other hand, it is preferable thatthe power supplied to the pairs of interlocking comb-shaped metallicelectrodes 33 is equal to or less than 10 W. When the power is equal toor less than 10 W, the power supplied to the pairs of interlockingcomb-shaped metallic electrodes 33 can be appropriately controlled whilesuppressing an overheating or the like of the pairs of interlockingcomb-shaped metallic electrodes 33, the piezoelectric element substrate,and the liquid under restrictions such as the power that can be suppliedand the capacity of the battery.

Generally, the decrease of the amount of power supplied to the pairs ofinterlocking comb-shaped metallic electrodes 33 would suppress theoverheating of the SAW module 30, however, it also causes the decreaseof the aerosol amount. Under such a premise, the amount of powersupplied to the pairs of interlocking comb-shaped metallic electrodes 33may be controlled by PWM (Pulse Width Modulation) in view of suppressingthe overheating of the SAW module 30. According to such a configuration,the overheating of the SAW module 30 can be suppressed by PWM whilesuppressing the decrease of the aerosol amount generated by SAW.

Under such power restrictions, it is preferable that the number of pairsof interlocking comb-shaped metallic electrodes 33 is equal to or morethan 10. According to such a configuration, it is possible to atomizethe liquid at a high atomizing efficiency. On the other hand, it ispreferable that the number of pairs of interlocking comb-shaped metallicelectrodes 33 is equal to or less than 80. According to such aconfiguration, the frequency bandwidth does not become too narrow, andthus, it is possible to achieve appropriate atomization even inconsideration of the manufacturing variation of the atomizing unit 100and variations of the resonant frequency under different operatingconditions (temperature, pressure, humidity, etc. . . . ).

The interval of the electrodes adjacent to each other and the width ofthe electrodes in the travel direction are inevitably determined inaccordance with the frequency of the power supplied to the pairs ofinterlocking comb-shaped metallic electrodes 33. The higher thefrequency, the narrower the interval of the electrodes adjacent to eachother, and the smaller the particle size of the aerosol. Under such arelationship, the desired particle size having the peak numberconcentration may be between 0.2 μm and 1.0 μm, for example. In such acase, it is preferable that the frequency is equal to or more than 20MHz. According to such a configuration, it is possible to keep theparticle size having the peak number concentration within a range of thedesired particle size. On the other hand, it is preferable that thefrequency is equal to or less than 200 MHz. Such a configuration mayensure that the interval of the electrodes do not become too narrow sothat it is less likely to cause short-circuiting of electrode at powershigher than the required minimum power (3 W, for example).

As described above, it should be noted that as a result of extensivestudies, the inventors obtained a new finding that, under the conditionwhere the power that can be supplied to the pairs of interlockingcomb-shaped metallic electrodes 33 is limited, the number of pairs ofinterlocking comb-shaped metallic electrodes 33 is determined based onthe atomizing efficiency of the aerosol. It also should be noted thatthe inventors obtained a new finding that the interval (that is, thefrequencies) of the electrodes are determined in accordance with thefrequency set based on the desired particle size of the aerosol.Further, it should be noted that the inventors obtained, based on thefinding that the atomizing efficiency may change depending on theinterval (that is, the frequencies or the desired particle sizes) of theelectrodes, a new finding that the number of pairs of interlockingcomb-shaped metallic electrodes 33 is determined based on the desiredaerosol. The desired aerosol is an aerosol in which the aerosol havingthe desired particle size is included in a desired distribution.

Further, as a result of extensive studies, the inventors obtained a newfinding that the atomizing efficiency of the aerosol is high when aratio (hereinafter, “R”) of a length (hereinafter, “H”) of theoverlapping portion of the pairs of interlocking comb-shaped metallicelectrodes 33 to a wavelength (hereinafter, “λ₀”) of the SAW is within apredetermined range. It is preferable that R (=H/λ0) is equal to or morethan 10 and equal to or less than 150. Further, it is preferable that Ris less than 70, preferably equal to or less than 50. Here, λ₀ isrepresented by a ratio (v/f) of a frequency (hereinafter, “f”) for thepower supplied to the pairs of interlocking comb-shaped metallicelectrodes 33 to a propagation velocity (hereinafter, “v”) of the SAW.Where f has a correlation with the interval of the electrodes and thewidth of the electrodes in the travel direction, and v has a correlationwith the type (characteristic) of the piezoelectric element substrate onwhich the pairs of interlocking comb-shaped metallic electrodes 33 areprovided. In other words, it is preferable that the length of theoverlapping portion of the pairs of interlocking comb-shaped metallicelectrodes 33, the interval of the electrodes, and the type of thepiezoelectric element substrate are determined so that a relationship of10≤R≤150 is satisfied. According to such a configuration, it is possibleto provide the atomizing unit 100 having a high atomizing efficiency ofthe aerosol.

(Shape of Penetrated Aperture)

A shape of a penetrated aperture according to the embodiment will bedescribed below. FIG. 5 is a diagram for describing a mechanism ofgenerating an aerosol.

As illustrated in FIG. 5, of the liquid exposed from the penetratedaperture 34, a portion relatively close to a portion coming in contactwith the SAW configures a thin film portion 71. Of the liquid exposedfrom the penetrated aperture 34, a portion relatively far from theportion coming in contact with the SAW configures a thick film portion72. The particle size of an aerosol 81 atomized from the thin filmportion 71 is smaller than the particle size of an aerosol 82 atomizedfrom the thick film portion 72. Therefore, if the desired particle sizeis comparatively small particle size (for example, 0.2 μm to 1.0 μm), itis effective to increase the area of the thin film portion 71 in theplanar view of the piezoelectric element substrate 31 viewed from theside of the front surface 31F. From such a perspective, it is preferablethat the penetrated aperture 34 has a shape in which the maximum lengthL_(MAX) is greater than the maximum width W_(MAX).

Further, if assuming that the penetrated aperture has a circular shapehaving a diameter corresponding to the maximum length L_(MAX), the areaof the liquid exposed from the penetrated aperture becomes too large,and thus, the liquid is likely to flow out above the piezoelectricelement substrate 31 when a user diagonally tilts the flavor inhaler 1.From such a perspective also, it is preferable that the penetratedaperture 34 has a shape in which the maximum length L_(MAX) is greaterthan the maximum width W_(MAX).

Operation and Effect

According to the embodiment, the number of pairs of interlockingcomb-shaped metallic electrodes 33 is determined based on the desiredaerosol. Therefore, in the atomizing unit 100 where the power that canbe supplied to the pairs of interlocking comb-shaped metallic electrodes33 is limited, it is possible to provide an appropriate atomizing unitby improving the atomizing efficiency of the liquid.

[First Modification]

A first modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the first modification, similarly to the embodiment, the penetratedaperture 34 has a shape in which the maximum length L_(MAX) is greaterthan the maximum width W_(MAX). Under such premise, as illustrated inFIG. 6, the penetrated aperture 34 is provided so as to reduceinterference between a reflected wave of the SAW reflected by thepenetrated aperture 34 and the SAW generated by the pairs ofinterlocking comb-shaped metallic electrodes 33. Specifically, it ispreferable that the longitudinal axis of the penetrated aperture 34 hasan inclination with respect to the orthogonal direction B. Thelongitudinal axis of the penetrated aperture 34 may have an inclination30° or more and 45° or less with respect to the orthogonal direction B.It is noted that the shape of the penetrated aperture 34 is not limitedto the elliptical shape illustrated in FIG. 6 and may be a rectangularshape.

Further, the penetrated aperture 34 may have a shape other than theelliptical shape and the rectangular shape. Even in such a case, thepenetrated aperture 34 is provided so as to reduce the interferencebetween the reflected wave of the SAW reflected by the penetratedaperture 34 and the SAW generated by the pairs of interlockingcomb-shaped metallic electrodes 33. For example, at least a part of thepenetrated aperture 34 is defined by an edge line where the penetratedaperture 34 comes in contact with the SAW. The edge line has aninclination with respect to the orthogonal direction B to the traveldirection A of the SAW. Here, the edge line may have a portion parallelto the orthogonal direction B. However, it is preferable that theportion of at least a half or more of the edge line has an inclinationwith respect to the orthogonal direction B. It is preferable that theportion of at least a half or more of the edge line has an inclinationof 30° or more and 45° or less with respect to the orthogonal directionB. If the penetrated aperture 34 is an elliptical shape or a rectangularshape, the longitudinal axis of the penetrated aperture 34 may have aninclination of 30° or more and 45° or less with respect to theorthogonal direction B.

According to such a configuration, the SAW generated by applying avoltage to the pairs of interlocking comb-shaped metallic electrodes 33at a high frequency (resonant frequency) is not easily interfered by thereflected wave of the SAW reflected at the penetrated aperture 34.Therefore, the tolerance of the piezoelectric element substrate 31improves and the atomizing efficiency of the aerosol also improves.

[Second Modification]

A second modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the second modification, the SAW module 30 has a separation wall 37separating the liquid exposed from the penetrated aperture 34 and thedisposition portion 30A. It is preferable that the separation wall 37entirely covers the disposition portion 30A. Further, the separationwall 37 may be configured to separate the air flow path extending fromthe inlet 51 to the outlet 52 and the disposition portion 30A. Accordingto such a configuration, it is possible to suppress the deterioration ofthe pairs of interlocking comb-shaped metallic electrodes 33 caused dueto adherence of the liquid and collision of air introduced from theinlet 51.

As illustrated in FIG. 7, the separation wall 37 may be provided on thefront surface 31F so as to come in contact with the front surface 31F ofthe piezoelectric element substrate 31 between the disposition portion30A and the penetrated aperture 34. The separation wall 37 may not coverthe entire piezoelectric element substrate 31. Typically, the separationwall 37 may be positioned at a minimum of 0.5 mm far from the edge(correspond to the typical thin film width). According to such aconfiguration, it is possible to ensure the suppression of thedeterioration of the pairs of interlocking comb-shaped metallicelectrodes 33 caused due to adherence or the like of the liquid.

In such a case, the separation wall 37 may be provided on the frontsurface 31F so as to come in contact with the front surface 31F of thepiezoelectric element substrate 31 between the disposition portion 30Aand a atomization zone when the atomization zone is provided at a sideof the pairs of interlocking comb-shaped metallic electrodes 33 relativeto the penetrated aperture 34.

As illustrated in FIG. 8, the separation wall 37 may be provided on thefront surface 31F so as not to come in contact with the front surface31F of the piezoelectric element substrate 31 between the dispositionportion 30A and the penetrated aperture 34. It is possible to suppress,if not eliminate, the deterioration of the pairs of interlockingcomb-shaped metallic electrodes 33 caused due to adherence or the likeof the liquid while avoiding a situation where propagation of the SAW isblocked by the separation wall 37. Further, a gap between the separationwall 37 and the front surface 31F provided for the propagation of theSAW may be approximately several microns. Such a gap can sufficientlysuppress the deterioration of the pairs of interlocking comb-shapedmetallic electrodes 33.

In such a case, the separation wall 37 may be provided on the frontsurface 31F so as not to come in contact with the front surface 31F ofthe piezoelectric element substrate 31 between the disposition portion30A and a atomization zone when the atomization zone is provided at aside of the pairs of interlocking comb-shaped metallic electrodes 33relative to the penetrated aperture 34.

[Third Modification]

A third modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the third modification, as illustrated in FIG. 9, a hydrophilic layer38 continuous from the penetrated aperture 34 is provided on the frontsurface 31F of the piezoelectric element substrate 31 between the pairsof interlocking comb-shaped metallic electrodes 33 and the penetratedaperture 34. For example, the hydrophilic layer 38 is configured by amaterial such as Teflon (trademark) resin, glass fiber, and the like.The hydrophilic layer 38 can be formed by a generally known hydrophilictreatment technology. For example, the hydrophilic treatment technologymay be a formation of a hydrophilic polymer film such as acetate, adiamond-like carbon film forming treatment, plasma treatment, surfaceroughening treatment, or a combination thereof. According to such aconfiguration, the liquid exposed from the penetrated aperture 34 easilymoves to the hydrophilic layer 38 and a thin film of the liquid iseasily formed on the hydrophilic layer 38. Accordingly, it is possibleto generate an aerosol having a small particle size from the thin filmformed on the hydrophilic layer 38. For example, if the desired particlesize is a comparatively small particle size (for example, 0.2 μm to 1.0μm), it is preferable that the hydrophilic layer 38 is provided.

[Fourth Modification]

A fourth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the fourth modification, a display device configured to display astate of the flavor inhaler 1 is provided. The display device may beprovided on an exterior surface of the housing 1X of the flavor inhaler1, or may be separately provided from the flavor inhaler 1. If thedisplay device is separated from the flavor inhaler 1, the displaydevice has a function of performing communication with the flavorinhaler 1. The display device includes a display such as a liquidcrystal or an organic EL. The display device may display the remainingamount of the liquid stored in the liquid storage unit 200, and maydisplay a count of puff actions executed by the user.

[Experiment Result]

(First Experiment) A first experiment will be described below. In thefirst experiment, the atomization state of the aerosol was visuallyconfirmed by modifying the number of pairs of interlocking comb-shapedmetallic electrodes 33. FIG. 10 is a diagram illustrating a result ofthe first experiment.

In a sample of N=20, the number of pairs of interlocking comb-shapedmetallic electrodes 33 was 20 and the power of 9.5 W was applied to thepairs of interlocking comb-shaped metallic electrodes 33 at a frequencyof 46.09 MHz. In a sample of N=40, the number of pairs of interlockingcomb-shaped metallic electrodes 33 was 40 and the power of 9.0 W wasapplied to the pairs of interlocking comb-shaped metallic electrodes 33at a frequency of 46.42 MHz. In a sample of N=80, the number of pairs ofinterlocking comb-shaped metallic electrodes 33 was 80 and the power of8.0 W was applied to the pairs of interlocking comb-shaped metallicelectrodes 33 at a frequency of 46.505 MHz.

As illustrated in FIG. 10, it was confirmed that an aerosol amount ofthe sample of N=40 is larger than an aerosol amount of the sample ofN=20, and an aerosol amount of the sample of N=80 is larger than theaerosol amount of the sample of N=40. From such experimental results, itwas visually confirmed that the atomizing efficiency increases as thenumber of pairs of interlocking comb-shaped metallic electrodes 33increases.

It is noted that an experiment was also performed on a sample where thenumber of pairs of interlocking comb-shaped metallic electrodes 33 was160, and it was confirmed that the atomization did not occur in such asample at similar power. Such a result is considered to be causedbecause a frequency that can be used became too narrow due to an NBWbecoming too narrow, and thus, appropriate atomization did not occur dueto the technical difficulty to drive the device at the most efficientfrequency at all times, as described in a second experiment.

(Second Experiment)

A second experiment will be described below. In the second experiment,an NBW was confirmed by modifying the number of pairs of interlockingcomb-shaped metallic electrodes 33. FIG. 11 is a table showing a resultof the second experiment. In FIG. 11, “N” is the number of pairs ofinterlocking comb-shaped metallic electrodes 33. “Frequency” is afrequency of the AC voltage applied to the pairs of interlockingcomb-shaped metallic electrodes 33. “NBW” is the frequency bandwidthcentered around the SAW resonant frequency in which a magnitude of thepower reflection coefficient of the SAW is smaller than a thresholdvalue. A smaller magnitude of the power reflection coefficient of theSAW means more electrical energy is converted to mechanical energy. Thatis, the maximum energy conversion is achieved in the NBW which is thefrequency bandwidth centered around the SAW resonant frequency.

As shown in FIG. 11, it was confirmed that the NBW (Null Bandwidth)becomes narrower as the number of pairs of interlocking comb-shapedmetallic electrodes 33 increases. As described above, for the sample ofN=160, it was confirmed that the frequency that can be used became toonarrow due to the NBW becoming too narrow, and thus, appropriateatomization did not occur.

As explained above, it was confirmed, from the result of the firstexperiment, that the atomizing efficiency improves as the number ofpairs of interlocking comb-shaped metallic electrodes 33 increases;however, it was confirmed, from the result of the second experiment,that the atomizing efficiency rather decreases if the number of pairs ofinterlocking comb-shaped metallic electrodes 33 is too large. That is,from the results of the first experiment and the second experiment, itwas confirmed that it is preferable to determine the number of pairs ofinterlocking comb-shaped metallic electrodes 33, based on the atomizingefficiency of the aerosol. In other words, it was confirmed that it ispreferable that the number of pairs of interlocking comb-shaped metallicelectrodes 33 is determined so as to satisfy a condition in which theNBW does not fall below a predetermined width and the amount of aerosolis equal to or more than the threshold value.

(Third Experiment)

A third experiment will be described below. The effect of the frequencyon the particle diameter (median volume based Dv50) was confirmed forthree samples. FIG. 12 is a diagram illustrating a result of a thirdexperiment.

“Straight IDT-2.25 mm” refers to a sample including the pairs ofinterlocking comb-shaped metallic electrodes 33 of a linear shape havinga length of 2.25 mm. “Straight IDT-4.5 mm” refers to a sample includingthe pairs of interlocking comb-shaped metallic electrodes 33 of a linearshape having a length of 4.5 mm. “Focussed IDT-50°” refers to a sampleincluding the pairs of interlocking comb-shaped metallic electrodes 33of a fan shape having a length of 2.25 mm and a central angle of 50°.

As illustrated in FIG. 12, it was confirmed that the average volume size(Dv 50) becomes smaller as the frequency increases, regardless of thedesign of the pairs of interlocking comb-shaped metallic electrodes 33.According to such a result, it was confirmed that it might be sufficientthat the interval (that is, frequencies) of the electrodes and the widthof the electrodes are determined based on a desired particle size of theaerosol.

[Fifth Modification]

A fifth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the fifth modification, an amplitude of a high-frequency voltageapplied to the pairs of interlocking comb-shaped electrodes 33 will bedescribed.

Specifically, in the fifth modification, the controller 400 periodicallychanges the amplitude of the high frequency voltage applied to the pairsof interlocking comb-shaped electrodes 33. According to such aconfiguration, it is possible to suppress droplets from scattering fromthe liquid guided to the front surface 31F of the piezoelectric elementsubstrate 31. Accordingly, the liquid can be effectively used and stableaerosol atomization can be realized. In detail, the aerosol is atomizedfrom the liquid (the thin film portion) at near-side of the pairs ofinterlocking comb-shaped electrodes 33 upon the application of the highvoltage, and the supply of the liquid decreased by the atomization ispromoted upon the application of the low voltage. A generation of coarseparticles can be suppressed and the atomizing amount of fine particlescan be decreased by repeating such operations. Note that the highvoltage and the low voltage are repeated around 100 Hz.

For example, as illustrated in FIG. 13, the periodic amplitude of thehigh frequency voltage may draw a sinusoidal wave shape, draw arectangular wave shape, draw a triangular wave shape, and draw asawtooth wave shape. In particular, it is preferable to apply a highfrequency voltage so that the periodic amplitude of the high frequencyvoltage draws a rectangular wave shape.

[Sixth Modification]

A sixth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the sixth modification, a profile of the optimum frequency of thevoltage applied to the pairs of interlocking comb-shaped electrodes 33will be described. The optimum frequency is a resonance frequency of theSAW (for example, the center frequency of the NBW described above) inwhich the magnitude of the power reflection coefficient of the SAW issmaller than a threshold value.

Firstly, a characteristic where the optimum frequency varies accordingto a relationship between a liquid supply speed (μl/sec) of the liquidguided to the front surface 31F of the piezoelectric element substrate31 and a time will be described. Specifically, as illustrated in FIG.14, samples (12 samples in FIG. 14) different in liquid supply speedwere prepared and the relationship between a time for applying a voltageto the pairs of interlocking comb-shaped electrodes 33 and the optimumfrequency was confirmed. Note that the width of the pairs ofinterlocking comb-shaped electrodes 33 is constant. According to such aconfirmation result, it can be seen that the optimum frequency varieswith a lapse of time, and it can also be seen that such a variance isdifferent depending on each liquid supply speed. Therefore, thecontroller 400 can improve the atomizing efficiency of the aerosol bymonitoring the optimum frequency, which varies according to the liquidsupply speed and the time, and supplying the liquid at the monitoredoptimum frequency.

Secondly, a characteristic where the optimum frequency varies accordingto a relationship between an output (W) of the SAW generated by applyinga high frequency voltage to the pairs of interlocking comb-shapedelectrodes 33 and a time will be described. Specifically, as illustratedin FIG. 15, samples (5 samples in FIG. 15) different in SAW output wereprepared, and the relationship between the time for applying a voltageto the pairs of interlocking comb-shaped electrodes 33 and the optimumfrequency was confirmed. Note that the width of the pairs ofinterlocking comb-shaped electrodes 33 is constant. According to such aconfirmation result, it can be seen that the optimum frequency varieswith a lapse of time, and it can also be seen that such a variance isdifferent depending on each output of the SAW. Therefore, the controller400 can improve the atomizing efficiency of the aerosol by monitoringthe optimum frequency, which varies according to the output of the SAWand the time, and supplying the liquid at the monitored optimumfrequency.

[Seventh Modification]

A seventh modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the seventh modification, a relationship between the liquid supplyspeed (μl/sec) of the liquid guided to the front surface 31F of thepiezoelectric element substrate 31 and the output (W) of the SAWgenerated by applying a high frequency voltage to the pairs ofinterlocking comb-shaped electrodes 33 will be described.

Firstly, as illustrated in FIG. 16, the controller 400 graduallyincreases the output of the SAW from a time tStart so that the output ofthe SAW reaches a desired level at a time t2. The controller 400 setsthe output of the SAW to zero at a time tEnd. On the other hand, thecontroller 400 increases the liquid supply speed to a desired level at atime t1. The controller 400 sets the liquid supply speed to zero at thetime tEnd. The time t1 may be between the time tStart and the time t2.

Secondly, as illustrated in FIG. 17, the controller 400 graduallyincreases the output of the SAW from the time tStart so that the outputof the SAW reaches the desired level at the time t2. The controller 400sets the output of the SAW to zero at the time tEnd. On the other hand,the controller 400 gradually increases the liquid supply speed from thetime t1 so that the liquid supply speed reaches a desired level at atime t3. The controller 400 sets the liquid supply speed to zero at thetime tEnd. The time t1 may be between the time tStart and the time t2.The time t3 may be after the time t2.

Note that the time tStart may be a timing at which the start of the puffaction is detected by the sensor 300 or a timing at which a button forperforming the puff action is pressed. The time tEnd may be a timing atwhich the end of the puff action is detected by the sensor 300 or atiming at which the button for performing the puff action is no longerpressed.

As illustrated in FIG. 16 and FIG. 17, the output of the SAW graduallyincreases from the time tStart and the liquid supply speed startsincreasing at the time t1 after the time tStart, and thus, it ispossible to suppress scattering of droplets having a large diameter fromthe liquid guided to the front surface 31F of the piezoelectric elementsubstrate 31 in an initial phase during which the output (W) of the SAWincreases. Further, as illustrated in FIG. 17, scattering of dropletshaving a large diameter can be suppressed by gradually increasing theliquid supply speed.

[Eighth Modification]

An eighth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the eighth modification, a detector configured to detect a state ofthe aerosol is provided. For example, the controller 400 may feedback anerror such as a poor aerosol generation, based on a detection result ofthe detector. The detector may be a microphone sensor configured todetect a weak noise caused by the aerosol generation.

As illustrated in FIG. 18, a detector 39 may be provided on the rearsurface 31B of the piezoelectric element substrate 31. The detector 39is preferably provided on an opposite side of the liquid with thepiezoelectric element substrate 31 interposed therebetween.

As illustrated in FIG. 19, the detector 39 may be provided on the frontsurface 31F of the piezoelectric element substrate 31. If the traveldirection of the SAW is a direction P, the detector 39 may be providednext to the liquid in a direction Q orthogonal to the direction P. Thedetector 39 is preferably not in contact with the liquid.

As illustrated in FIG. 20, the detector 39 may be provided above thefront surface 31F of the piezoelectric element substrate 31, at aposition apart from the front surface 31F of the piezoelectric elementsubstrate 31. In order to suppress a contact between the detector 39 andthe aerosol, it is preferable that a shield 39A is provided between thedetector 39 and the aerosol.

[Ninth Modification]

A ninth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the ninth modification, a sensor configured to detect the liquidexposed from the penetrated aperture 34 is provided. For example, thecontroller 400 may control the liquid supplier 60 (liquid supply speed,and the like), based on a detection result of the sensor. According tosuch a configuration, it is possible to suppress an excessive supply ofthe liquid to the atomizer as well as drying up of the liquid at theatomizer by accurate pump control, and the stability of aerosolatomization is improved.

As illustrated in FIG. 21, a sensor 71 may be an electric conductivitysensor including a pair of tip ends (for example, tip ends 71A, 71B).The pair of tip ends are adjacent to the penetrated aperture 34 and areelectrically connected by the liquid exposed from the penetratedaperture 34. The sensor 71 detects a presence of the liquid based on theconductivity of the electric signal between the pair of tip ends.

As illustrated in FIG. 22, a sensor 72 may be an electric conductivitysensor including two or more pairs of tip ends (for example, tip ends72A, 72B, and the like). The two or more pairs of tip ends are adjacentto the penetrated aperture 34 and are electrically connected by theliquid exposed from the penetrated aperture 34. However, the positionswhere the pairs of tip ends are provided are different from each other.Based on the conductivity of the electrical signal between the pair oftip ends, the uniformity of the thin film can be monitored and thepresence of the liquid at the position where the pair of tip ends can bedetected by use of the sensor 72.

As illustrated in FIG. 23, a sensor 73 may be a sensor including anemitter (for example, an emitter 73A) configured to output apredetermined signal and a receiver (for example, a receiver 73B)configured to receive the predetermined signal. The emitter 73A and thereceiver 73B are disposed with the penetrated aperture 34 interposedtherebetween, and the sensor 73 detects the presence of the liquid basedon a transmission magnitude of the predetermined signal. The emitter 73Aand the receiver 73B may be configured of a thin film solid pad.

As illustrated in FIG. 24, a sensor 74 may be a SAW sensor including anemitter (for example, an emitter 74A) configured to output the SAW and areceiver (for example, a receiver 74B) configured to receive the SAW.The emitter 74A and the receiver 74B are disposed with the penetratedaperture 34 interposed therebetween, and the sensor 74 detects thepresence of the liquid based on the transmission magnitude of the SAW.The emitter 74A and the receiver 74B may be configured of a thin filmIDT.

As illustrated in FIGS. 25 (a) and 25 (b), a sensor 75 may be acapacitive sensor including one or more pairs of electrodes (forexample, tip ends 75A, 75B and the like). In such a case, the one ormore pairs of electrodes are disposed across the liquid disposed on theatomization zone. The sensor 75 detects the presence or non-presence ofthe liquid based on a difference of capacitance caused by the presenceor non-presence of the liquid. In such a case, the penetrated aperture34 can be omitted.

[Tenth Modification]A tenth modification of the embodiment will bedescribed, below. A difference from the embodiment will be mainlydescribed below.

In the tenth modification, an example of a combination of the eighthmodification and the ninth modification will be described. Asillustrated in FIG. 26, the SAW module 30 includes a detector 81, asensor 82, and a depth sensor 83.

Similar to the detector 39 described in the eighth modification, thedetector 81 detects the state of the aerosol. Similar to the electricconductivity sensor or the SAW sensor described in the ninthmodification, the sensor 82 detects the liquid exposed from thepenetrated aperture 34. The depth sensor 83 detects a depth of theliquid (a surface water level of the liquid) in the penetrated aperture34. The depth sensor 83 may be an electric conductivity sensorconfigured to detect the presence of the liquid based on theconductivity of the electric signal.

In such a configuration, before and after the atomization of theaerosol, the controller 400 controls the liquid supplier 60 (the liquidsupply speed and the like), based on a detection result of the depthsensor 83, as illustrated in an upper part of FIG. 26. For example, thecontroller 400 controls the liquid supplier 60 so that the liquid ismaintained at a desired depth. According to such a configuration, aresponsiveness of the aerosol atomization improves.

During the atomization of the aerosol, the controller 400 feeds back anerror such as a poor aerosol generation, based on a detection result ofthe detector 81, as illustrated in a lower part of FIG. 26. Thecontroller 400 may notify the user of the error and may stop anoperation of the flavor inhaler 1 (for example, the atomizing unit 100).Further, the controller 400 controls the liquid supplier 60 (liquidsupply speed, and the like) based on a detection result of the sensor82. According to such a configuration, the stability of the aerosolatomization is improved.

Moreover, the liquid amount during the atomization can be controlledusing the depth sensor 83. The controller 400 controls the liquidsupplier 60 (the liquid supply speed and the like) based on thedetection result of the depth sensor 83 when the depth sensor 83 detectsa decrease of the liquid. According to such a configuration, the liquidamount can be kept at a desired level during the atomization and thestability of the aerosol atomization is improved.

Further, although not shown, two or more depth sensors, each havingdifferent detection depths, can be provided as the depth sensor 83. Insuch a case, it is easy to appropriately control the liquid amount in arange of the depth sensors having the different detection depths. Forexample, when the first depth sensor, which detects the first depth ofthe liquid, detects the liquid and the second sensor, which detects thesecond depth shallower than the first depth, does not detects theliquid, it is possible to detect the depth of liquid is between thefirst depth and the second depth.

[Eleventh Modification]

An eleventh modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the eleventh modification, a method of guiding the liquid on thefront surface 31F of the piezoelectric element substrate 31 will bedescribed. Specifically, as illustrated in FIG. 27, a supply port 34X, ahydrophilic layer 38A, a hydrophobic layer 38B, and a hydrophobic layer38C are provided on the front surface 31F of the piezoelectric elementsubstrate 31.

The supply port 34X is a point to which liquid is supplied. The supplyport 34X is provided outside a path of the SAW. Therefore, the supplyport 34X does not need to be the above-described penetrated aperture 34,and may be a point at which the liquid is supplied from a side of thefront surface 31F of the piezoelectric element substrate 31.

The hydrophilic layer 38A is continuous to the supply port 34X and has apattern for leading the liquid into the path of the SAW. The hydrophobiclayer 38B is provided on a near side to the pairs of interlockingcomb-shaped electrodes 33 than the hydrophilic layer 38A, and isprovided apart from the hydrophilic layer 38A. The hydrophobic layer 38Cis provided on a far side from the pairs of interlocking comb-shapedelectrodes 33 than the hydrophilic layer 38A, and is provided apart fromthe hydrophilic layer 38A. The movement of the liquid from hydrophiliclayer 38A can be restricted by the hydrophobic layers 38B and 38C, thecontact angle of SAW to the liquid can be reduced, and the efficiency ofthe aerosol atomization is improved.

According to such a configuration, the penetrated aperture 34 does notneed to be provided and thus, the coating layer 36 coating thepiezoelectric element substrate 31 can easily be provided.

[Twelfth Modification]

A twelfth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the twelfth modification, a method of supplying the liquid to thefront surface 31F of the piezoelectric element substrate 31 will bedescribed. Specifically, as illustrated in FIG. 28, a hydrophilic layer38D and a wick 90 are provided on the front surface 31F of thepiezoelectric element substrate 31.

The hydrophilic layer 38D is provided on the path of the SAW. Thehydrophilic layer 38D has a length L and a width W and configures anatomization zone for atomizing the aerosol. The wick 90 is continuous tothe hydrophilic layer 38D and supplies the liquid to the hydrophiliclayer 38D. The wick 90 may have a wick core 91 which keeps a shape ofthe wick 90, and a holding layer 92 which holds the liquid. The wickcore 91 contacts with the front surface 31F of the piezoelectric elementsubstrate 31 preferably formed of a metal or a plastic having a hardnesswhich can reflect the SAW transmitted on the piezoelectric elementsubstrate 31. The holding layer 92 may be configured of a capillarymember configured to supply the liquid by a capillary phenomenon.

According to such a configuration, the penetrated aperture 34 does notneed to be provided and thus, the coating layer 36 coating thepiezoelectric element substrate 31 can easily be provided.

[Thirteenth Modification]

A thirteenth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the thirteenth modification, a method of supplying the liquid to thefront surface 31F of the piezoelectric element substrate 31 will bedescribed. Specifically, as illustrated in FIG. 29, a hydrophilic layer38E and a member 84 are provided on the front surface 31F of thepiezoelectric element substrate 31. Further, a liquid storage unit 200and a driving unit 61 are provided on the front surface 31F of thepiezoelectric element substrate 31.

The hydrophilic layer 38E is provided on the path of the SAW andconfigures an atomization zone for atomizing the aerosol. The member 84may be a sensor configured to detect the presence of the liquid or adetector configured to detect the state of the aerosol.

The liquid storage unit 200 and a driving unit 61 configure a deviceconfigured to drop the liquid in the vicinity of the hydrophilic layer38E. For example, the liquid storage unit 200 may include a nozzleconfigured to store the liquid and drop the liquid. The driving unit 61may be a member (for example, a motor) configured to generate a driveforce for dropping the liquid from the nozzle.

According to such a configuration, the penetrated aperture 34 does notneed to be provided and thus, the coating layer 36 coating thepiezoelectric element substrate 31 can easily be provided.

[Fourteenth Modification]

A fourteenth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the fourteenth modification, a method of supplying the liquid to thefront surface 31F of the piezoelectric element substrate 31 will bedescribed. Specifically, as illustrated in FIG. 30 and FIG. 31, the SAWmodule 30 has a guide member 610 configured to guide the liquid. Thepiezoelectric element substrate 31 is coated with the coating layer 36.

The guide member 610 is provided on the front surface 31F of thepiezoelectric element substrate 31 at an edge portion of thepiezoelectric element substrate 31. The guide member 610 has a shapehaving a predetermined height from the front surface 31F of thepiezoelectric element substrate 31. The guide member 610 may be made ina material with high thermal conductivity (metal or ceramic, forexample). The guide member 610 includes a flow path 611, a temporarystorage unit 612, and a guide slit 613. The flow path 611 configures aflow path of the liquid. The temporary storage unit 612 temporarilystores the liquid supplied via the flow path 611. The guide slit 613 hasan inclination with respect to the front surface 31F of thepiezoelectric element substrate 31. The guide slit 613 guides the liquidoverflowing from the temporary storage unit 612 to the front surface 31Fof the piezoelectric element substrate 31 by the weight of the liquidand/or capillary force. Two or more guide slits may be provided as theguide slit 613.

According to such a configuration, the atomization zone can be disposedat a position apart from the edge portion of the piezoelectric elementsubstrate 31 by the guide member 610 provided at the edge portion of thepiezoelectric element substrate 31, and a detachment of the coatinglayer 36 can be suppressed at the edge portion. Further, the penetratedaperture 34 does not need to be provided and thus, the coating layer 36coating the piezoelectric element substrate 31 can easily be provided.

In the fourteenth modification, a case of supplying the liquid from therear surface 31B of the piezoelectric element substrate 31 isexemplified, however, the fourteenth modification is not limitedthereto. The liquid may be supplied from the side of the guide member610 or may be supplied from above the guide member 610. If the liquid issupplied from above the guide member 610, the above-described flow path611 may not be provided.

Alternatively, the liquid may be supplied via the penetrated aperture34. In such a case, the guide member 610 is provided so that the flowpath 611 communicates with the penetrated aperture 34, the atomizationzone can be disposed at a position apart from the edge portion of thepenetrated aperture 34, and the detachment of the coating layer 36 atthe edge portion can be suppressed.

Alternatively, as shown in FIG. 32, the SAW module 30 may have a guidemember 610A configured to guide the liquid. The guide member 610A isformed of a member such as a plastic or metal having a fine flow pathinside and provided on the front surface 31F of the piezoelectricelement substrate 31. The guide member 610A guides the liquidimpregnated in the guide member 610A to the fine space between the frontsurface 31F of the piezoelectric element substrate 31 and the guidemember 610A. The guide member 610A guides the liquid on the frontsurface 31F of the piezoelectric element substrate 31 from the finespace.

Alternatively, as shown in FIG. 33, the SAW module 30 may have a guidemember 610B configured to guide the liquid. The guide member 610B isformed of a member such as a plastic or metal having a fine flow pathinside and provided on the front surface 31F of the piezoelectricelement substrate 31. The guide member 610B guides the liquidimpregnated in the guide member 610B to the front surface 31F of thepiezoelectric element substrate 31 along a slant surface 613B of theguide member 610B.

According to the configurations shown if FIGS. 32 and 33, as same as theconfiguration shown in FIGS. 30 and 32, the atomization zone can bedisposed at a position apart from the edge portion of the piezoelectricelement substrate 31 and a detachment of the coating layer 36 can besuppressed at the edge portion.

[Fifteenth Modification]

A fifteenth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the fifteenth modification, a variation of a substrate configurationof the SAW module 30 will be described. Specifically, as illustrated inFIG. 34, the SAW module 30 includes a piezoelectric element substrate621, a plate 622, a buffer 623, and an atomization surface layer 624. InFIG. 34, a configuration other than the substrate configuration (forexample, the pairs of interlocking comb-shaped electrodes 33) isomitted.

The piezoelectric element substrate 621 is similar to the piezoelectricelement substrate 31 described above. The plate 622 is a substratedifferent from the piezoelectric element substrate 31, and is analuminum plate, for example. The buffer 623 is located on a frontsurface and a side surface of the piezoelectric element substrate 621and is configured by a buffer liquid that transmits the SAW generatedfrom the piezoelectric element substrate 621 to the atomization surfacelayer 624. For example, the buffer liquid is Glycerin. The atomizationsurface layer 624 is provided on the buffer 623 and the plate 622 and isprovided with an atomization zone for atomizing the aerosol. Forexample, the atomization surface layer 624 is configured of a stainlessplate. In such a case, the liquid may be supplied from a front surfaceside of the atomization surface layer 624.

According to such a configuration, the SAW can be transmitted to theatomization surface layer 624 that is different from the piezoelectricelement substrate 621, and a contact of the liquid (a flavor liquid)with the piezoelectric element substrate 621 can be avoided. Forexample, a penetrated aperture corresponding to the penetrated aperture34 described above may be provided in the plate 622.

[Sixteenth Modification]

A sixteenth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the sixteenth modification, a variation of a shape of the edgeportion of the piezoelectric element substrate 31 will be described in acase where the liquid is supplied from the rear surface 31B of thepiezoelectric element substrate 31. The edge portion is a portionadjacent to the atomization zone. The edge portion is subjected to afilleting and chamfering process. According to such a configuration, thedetachment of the coating layer 36 at the edge portion can be suppressedby reducing the energy density at the atomization zone.

Here, the chamfering process of the edge portion may be a linearchamfering process, as illustrated in FIG. 35, or a round chamferingprocess, as illustrated in FIG. 36. The edge portion may be an edgeportion of the penetrated aperture 34.

[Seventeenth Modification]

A seventeenth modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the seventeenth modification, a variation of the atomization zonewill be described. Specifically, as illustrated in FIG. 37, the SAWmodule 30 includes two or more shallow grooves 631 (here, grooves 631Ato 631D) as the atomization zone. Each of the grooves 631 has a shapeextending in a direction orthogonal to the travel direction of the SAW.The liquid is supplied to each of the grooves 631. An amount of liquidsupplied to each of the grooves 631 may be larger for a groove closer tothe pairs of interlocking comb-shaped electrodes 33. Although notillustrated in FIG. 34, the piezoelectric element substrate 31 is coatedby the coating layer 36.

According to such a configuration, the energy of the SAW is dispersed bytwo or more grooves and thus, a detachment of the coating layer 36 inthe atomization zone is suppressed, and the robustness of the conformalcoating in the edge portion would be increased.

[Eighteenth Modification]

An eighteenth modification of the embodiment will be described, below. Adifference from the embodiment will be mainly described, below.

In the eighteenth modification, a method of guiding the liquid on thefront surface 31F of the piezoelectric element substrate 31 will bedescribed. Specifically, as illustrated in FIG. 35, the SAW module 30has a printed electrode 641 to a printed electrode 643. Two liquidstorage units 200 (a liquid storage unit 200A and a liquid storage unit200B) are provided. A liquid stored in the liquid storage unit 200A maybe different from a liquid stored in the liquid storage unit 200B.

The printed electrode 641 to the printed electrode 643 transport theliquid by utilizing a voltage difference between printed electrodesadjacent to each other. For example, the printed electrode 641Atransports the liquid stored in the liquid storage unit 200A, and theprinted electrode 641B transports the liquid stored in the liquidstorage unit 200B. The printed electrode 642 transports a mixture ofliquids supplied from the printed electrode 641A and the printedelectrode 641B. The printed electrode 643A and the printed electrode643B transport a mixture of liquids supplied from the printed electrode642. Each of a part of the printed electrode 643A and a part of theprinted electrode 643B configures the atomization zone.

A width of the printed electrode configuring the atomization zone may belarger than a width of the printed electrode (for example, the printedelectrode 642) not configuring the atomization zone and may be actuatedin a specific manner to attract the bulk of liquid in two or moredifferent directions at the same time. According to such aconfiguration, the width of the printed electrode not configuring theatomization zone is small and thus, it is possible to save a space ofthe printed electrode not configuring the atomization zone. The bulk ofliquid is attracted in two or more different directions at the same timeand thus, the liquid in the atomization zone can be flattened and thecontact angle of the SAW to the liquid can be reduced.

[Nineteenth Modification]

A nineteenth modification of the embodiment will be described, below. Adifference from the embodiment will be mainly described, below.

In the nineteenth modification, a variation of the heat radiationmechanism will be described. Specifically, as illustrated in FIG. 39 toFIG. 41, a coating layer 651 and an adhesive layer 652 are provided onthe rear surface of the SAW module 30. The coating layer 651 may includemetal. The adhesive layer 652 may include solder.

Under such premise, as illustrated in FIG. 39, the SAW module 30 isadhered to a heat conductive member 653 and a circuit board 654 via theadhesive layer 652. The heat conductive member 653 includes a heatconductive member such as metal, and has a columnar portion 653A and aplate portion 653B. The columnar portion 653A penetrates the circuitboard 654, and the plate portion 653 B is disposed on the rear surfaceof the circuit board 654. The circuit board 654 is configured of amember easily adherable to the adhesive layer 652, and includes apenetrated aperture passing through the columnar portion 653A.

Alternatively, as illustrated in FIG. 40, the SAW module 30 is adheredto a heat sink 655 via the adhesive layer 652. The heat sink 655 isconfigured of a heat conductive member such as metal.

Alternatively, as illustrated in FIG. 41, the SAW module 30 may beadhered to the heat conductive member 653 and the circuit board 654 viathe adhesive layer 652, and the heat sink 655 may be adhered to theplate portion 653B (combination of FIG. 39 and FIG. 40).

[Twentieth Modification]A twentieth modification of the embodiment willbe described below. A difference from the embodiment will be mainlydescribed below.

In the twentieth modification, a variation of the liquid supplier willbe described. Here, a case where the liquid supplier has a liquidstorage unit will be exemplified.

Firstly, as illustrated in FIG. 42, the liquid supplier 60 may include ahousing 661, a pump 662, and a piston 663. The housing 661 includes aliquid 666 for driving the piston 663 and a liquid 667 for generating anaerosol. The liquid 666 and the liquid 667 are partitioned by the piston663. The housing 661 includes a flow path 661A for communicating thehousing 661 and the pump 662, and a flow path 661B for communicating thehousing 661 and the pump 662. The housing 661 includes a discharge port661C configured to discharge the liquid 667.

Here, the pump 662 moves the piston 663 by a reflux of the liquid 666.For example, the pump 662 advances the piston 663 by sucking up theliquid 666 via the flow path 661A and returning the liquid 666 to thehousing 661 via the flow path 661B. Thus, the pump 662 can discharge theliquid 667 from the discharge port 661C. The pump 662 may be a piezopump.

According to such a configuration, the liquid 666 used for dischargingthe liquid 667 does not mix with the liquid 667 and thus, thepossibility that an impurity is mixed into the liquid 667 can bereduced. Further, the liquid 667 that generates the aerosol does notpass through the pump 662 and thus, a deterioration of the liquid 667can be suppressed. Further, an amount of movement of the piston 663 canbe specified by the amount of reflux of the liquid 666, and a remainingamount of the liquid 667 can be specified by the amount of movement ofthe piston 663.

In FIG. 42, the liquid 666 is exemplified as a medium for driving thepiston 663, however, a gas may be used instead of the liquid 666.

Here, as shown in FIG. 43, the liquid supplier 60 may include the pump668 in addition to the configuration shown in FIG. 42. The pump 668moves the piston 663 by a reflux of the liquid 666. The pump 668retracts the piston 663 by sucking up liquid 666 via the flow path 669Aand returning the liquid 666 to the housing 661 via the flow path 669B.The pump 668 may be a piezo pump.

Secondly, as illustrated in FIG. 44, the liquid supplier 60 includes ahousing 671 and a bag 672. The housing 671 houses the bag 672 and an air676 and includes an inlet 671A configured to supply the air 676 into thehousing 671. The bag 672 houses the liquid 677 for generating theaerosol and includes a discharge port 672A configured to discharge theliquid 677. A discharge port 672A may be integrally formed with thehousing 671.

Here, the bag 672 is configured of a flexible member. Thus, when the air676 is supplied into the housing 671 from the inlet 671A, the bag 672can discharge the liquid 677 by a pressure of the air 676.

According to such a configuration, the air 676 used for ejecting theliquid 677 does not mix with the liquid 677 and thus, the possibilitythat an impurity is mixed into the liquid 677 can be reduced.

In FIG. 44, the air 676 is exemplified as a medium for pressurizing thebag 672, however, a liquid may be used instead of the air 676.

[Twenty First Modification]

A twenty first modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

Although not particularly mentioned in the embodiment, the piezoelectricelement substrate 31 may be cut out by laser cutting. According to sucha configuration, since the edge portion of the piezoelectric elementsubstrate 31 becomes smooth, the durability of the piezoelectric elementsubstrate 31 and the adhesion of the coating layer 36 are improved.

[Twenty Second Modification]

A twenty second modification of the embodiment will be described below.A difference from the embodiment will be mainly described below.

In the twenty second modification, as illustrated in FIG. 45, theatomizing unit 100 includes a top cover 710, a guide wall 711, and asensor 712. The atomizing unit 100 includes the piezoelectric elementsubstrate 31 and the pairs of interlocking comb-shaped metallicelectrodes 33 as described in the embodiment.

The top cover 710 is provided to cover a lateral and upper side of theaerosol atomized by SAW. An opening 710A is provided at an upper end ofthe top cover 710 to lead out the aerosol.

The guide wall 711 is provided to contact with an inner wall of the topcover 710 not allowing a space with the inner wall of the top cover 710.The guide wall 711 is positioned away from the piezoelectric elementsubstrate 31, the penetrated aperture 34 is provided between thepiezoelectric element substrate 31 and the guide wall 711. In FIG. 45,guide walls 711A and 711B are provided as the guide wall 711.

The first liquid is provided to the penetrated aperture 34A providedbetween the piezoelectric element substrate 31 and the guide wall 711Afrom the liquid supplier (a syringe pump, for example). Similarly, thesecond liquid is provided to the penetrated aperture 34B providedbetween the piezoelectric element substrate 31 and the guide wall 711Bfrom the liquid supplier (a syringe pump, for example). The first liquidand the second liquid may be the same kind of liquid or the differentkind of the liquid.

The sensor 72 detects the liquid exposed from the penetrated aperture 34as same as the ninth modification or the like. The liquid supplier 60(supplying speed of the liquid) can be controlled based on the detectionresult of the sensor 72. In FIG. 45, a sensor 72A detects the firstliquid exposed from the penetrated aperture 34A and a sensor 72B detectsthe second liquid exposed from the penetrated aperture 34B as the sensor72.

Although not shown in FIG. 45, a sealing member such as O-ring orpacking may be provided to suppress a leakage of the first liquid andthe second liquid.

[Twenty Third Modification]

A twenty third modification of the embodiment will be described below. Adifference from the embodiment will be mainly described below.

In the twenty third modification, as illustrated in FIG. 46, theatomizing unit 100 includes an impactor 721 and a separation wall 722 inaddition to the configuration in FIG. 45.

The impactor 721 is positioned to cover the atomization zone of thefirst liquid. The impactor 721 has a function to trap the coarseparticles (about 10 microns, for example) included in the aerosolgenerated from the first liquid by inertial impaction. The fineparticles are guided to the opening 710A (that is the mouth of user)from a void between the impactor 721 and the piezoelectric elementsubstrate 31 without trapped by the impactor 721.

The coarse particles trapped by the impactor 721 may be returned to theatomization zone. The coarse particles returned to the atomization zonemay be re-atomized. Alternately, the coarse particles trapped by theimpactor 721 can be collected by a collecting member such as a porousabsorber or a reservoir without re-used for the atomization.

In FIG. 46, although a impactor is not provided which covers theatomization zone of the second liquid, the impactor may be providedwhich covers the atomization zone of the second liquid. The first liquidand the second liquid may be the same kind of liquid or the differentkind of the liquid. The aerosol including the particles of the desiredsize can be supplied by providing the impactor or not.

Although FIG. 46 shows an example that the first liquid and the secondliquid are atomized independently, the first liquid and the secondliquid may be atomized after mixed. The impactor 721 may be positionedto cover the atomization zone of the mixed liquid or positioned at themouthpiece.

The separation wall 722 is provided between the atomization zone of thefirst liquid and the atomization zone of the second liquid. The separtonwall 722 suppress the mix of the aerosol generated from the first liquidand the aerosol generated from the second liquid until the aerosol isled out from the opening 710A. According to such a configuration, themixing of the aerosol generated from the different kind of liquids canbe suppressed when the first liquid and the second liquid are thedifferent kind. Specifically, it is preferable to suppress the mixing ofthe aerosol generated from the different kind of liquids, when thecoarse particles generated from respective liquids are re-used.

Further, the separation wall 722 can trap the extra-large particles(about 100 micron, for example) larger than the coarse particles trappedby the impactor 721. Moreover, the separation wall 722 can trap theextra-large particles about 100 micron when the impactor 712 is notprovided.

The extra-large particles trapped by the separation wall 722 may bereturned to the atomization zone. The extra-large particles returned tothe atomization zone may be re-atomized. Alternately, the extra-largeparticles trapped by the separation wall 722 can be collected by acollecting member such as a porous absorber or a reservoir withoutre-used for the atomization.

Although the impactor 721 is provided in FIG. 46, a filter 725 may beprovided instead of the impactor 721 as shown in FIG. 47. The filter 725may be a fibrous layer filter or a granular packed layer provided at anarbitrary position within the top cover 710. It is possible to designthe trap efficiency of the coarse particles appropriately by changing afiber diameter, a grain size, a filling ratio, and a filling length ofthe filter 721.

The top cover 710 may include an inlet 726. The flow path of air oraerosol from the inlet 726 to the opening 710A is formed in the topcover 710. According to such a configuration, it is possible to suppressa retention of aeroson in the top cover 710 and to optimize an amount ofthe aerosol delivered to the mouth. The top cover 710 in FIGS. 45 and 46may include the inlet 726.

[Experiment Result]

The experiment result would be described below. In the experiment, adistilled water is used as the liquid and 50 MHz is used as thefrequency of the voltage applied to the pairs of interlockingcomb-shaped metallic electrodes. In the experiment, a diameterdistribution of particles included in aerosol. FIG. 48 shows theexperiment result.

FIG. 48 shows the diameter distributions observed based on the number ofparticles and the volume of the particles. Regarding the number ofparticles, it is observed that the diameter distribution has the singlepeak. However, regarding the volume of particles, it is observed thatthe diameter distribution has two peaks (about 0.6 micron and about 8micron).

In such a case, it is possible to adjust the diameter distribution basedon the volume of particles to have the single peak (about 0.6 micron) byselectively trapping the particles of 8 micron by use of the impactor721 or the filter 725 described in the twenty third modification (seeFIG. 46 or 47).

[Twenty-Fourth Modification]

FIG. 49 is a perspective view showing an example of an exterior of theunit excluding the sensor 300, the controller 400, and the power source500 of the flavor inhaler 1 shown in FIG. 1. FIG. 50 is a longitudinalsection of the unit shown in FIG. 49. FIG. 51 is an exploded perspectiveview of the unit shown in FIG. 49. As shown in FIG. 49 to FIG. 51, aunit 1000 comprises a mouthpiece 1001D, an atomizing unit 1100, a firstliquid storage unit 1200A, and a second liquid storage unit 1200B. Notethat, in the following description, the “flavor inhaler” may simply bereferred to as an “inhaler.” In addition to the flavor components, anycomponents, which can be inhaled, can be inhaled by use of the“inhaler.”

The first liquid storage unit 1200A and the second liquid storage unit1200B are housed in a housing 1202 which is a component of the housing1X shown in FIG. 1. In the present modified example, the first liquidstorage unit 1200A comprises a cylinder 1204A and a piston 1206A, andfirst liquid is stored in a space defined by the cylinder 1204A and thepiston 1206A. Similarly, the second liquid storage unit 1200B comprisesa cylinder 1204B and a piston 1206B, and second liquid is stored in aspace defined by the cylinder 1204B and the piston 1206B. The firstliquid storage unit 1200A and the second liquid storage unit 1200B maybe integrally constructed as a cartridge for making them to beattachable/detachable in a simultaneous manner.

In the present modified example, the first liquid and the second liquidmay be the same liquid. Alternatively, the first liquid and the secondliquid may be different from each other. The first liquid may compriseat least nicotine. In addition, the first liquid may comprise an acidsuch as malic acid, citric acid, tartaric acid, or the like, for forminga salt with nicotine, for example. Further, the first liquid maycomprise at least one of erythritol, a salt, an inosinic acid, aglutamic acid, a succinic acid, sodium salts of these, potassium saltsof these, isohumulone, cucurbitacin, curcumine, falcarindiol, naringin,quassin, quinine, riboflavin, thiamine, and catechin, as a tastecomponent. Also, the first liquid may comprise at least one ofcapsaicin, piperine, eugenol, allicin, allyl isothiocyanate, gingerol,cinnamic aldehyde, and glycosides of these, as a component (asomatosensory component) for making somatic sense to be expressed in auser who inhaled the component.

The second liquid may comprise a flavor component which includes atleast one of menthol, limonene, citral, linalool, vanillin, carvone, andglycosides of these. The second liquid may comprise an emulsifier, andmay be in an emulsified state. Regarding the emulsifier, it may bepossible to use emulsifiers such as glycerine fatty acid ester, sorbitanfatty acid ester, propylene glycol fatty acid ester, sucrose fatty acidester, lecithin, saponin, sodium caseinate, oxyethylene fatty acidalcohol, sodium oleate, a morpholine fatty acid salt, polyoxyethylenehigher fatty acid alcohol, calcium stearoyl lactate, monoglycerideammonium phosphate, and so on. The second liquid may comprise a solventsuch as glycerin, propylene glycol, ethanol, or the like. In the casethat a hydrophobic flavor component is to be used in the second liquid,it can be made to have the form of a solution by dissolving the flavorcomponent in the solvent. Further, the second liquid may comprise atleast one of erythritol, a salt, an inosinic acid, a glutamic acid, asuccinic acid, sodium salts of these, potassium salts of these,isohumulone, cucurbitacin, curcumine, falcarindiol, naringin, quassin,quinine, riboflavin, thiamine, and catechin, as a taste component. Also,the second liquid may comprise at least one of capsaicin, piperine,eugenol, allicin, allyl isothiocyanate, gingerol, cinnamic aldehyde, andglycosides of these, as a component (a somatosensory component) formaking somatic sense to be expressed in a user who inhaled thecomponent. At least one of the first liquid and the second liquid may bethe same as liquid stored in the liquid storage unit 200 which has beenexplained in relation to FIG. 1.

As shown in FIG. 50, the housing 1202 houses a motor 1208A and a gearbox 1210A. Electric power is supplied from the power source 500 shown inFIG. 1 to the motor 1208A. The gear box 1210A can convert driving forcein the direction of rotation of the motor 1208 A to driving force in thedirection of an axis of the piston 1206A. Also, the gear box 1210A canchange the speed of rotation of the motor 1208A. Similarly, the housing1202 houses a motor 1208B and a gear box 1210B, and a piston 1206B isdriven by the motor 1208B and the gear box 1210B. Electric power issupplied from the power source 500 shown in FIG. 1 to the motor 1208B.That is, in the present modified example, a liquid supplier forsupplying liquid from the first liquid storage unit 1200A and the secondliquid storage unit 1200B is constructed by using, as componentsthereof, the motors 1208A and 1208B and the gear boxes 1210A and 1210B.Note that it may be possible to drive both the pistons 1206A and 1206Bby use of a single motor and a single gear box.

As shown in FIG. 50, the atomizing unit 1100 is arranged at a positionabove the first liquid storage unit 1200A and the second liquid storageunit 1200B, and fixed to an upper part of the housing 1202 by a fixture1002 such as a screw and so on. Also, the mouthpiece 1001D is fixed toan upper part of the atomizing unit 1100 by a fixture 1004 such as ascrew and so on.

As shown in FIG. 51, the atomizing unit 1100 is covered by a first cover1106 and a second cover 1107. The first cover 1106 comprises, on itsupper surface, a first opening part 1102 and a second opening part 1104.The first opening part 1102 is constructed in such a manner that firstaerosol, which is generated by atomizing the first liquid, passesthrough it, as will be explained later. The second opening part 1104 isconstructed in such a manner that second aerosol, which is generated byatomizing the second liquid, passes through it, as will be explainedlater.

Next, the atomizing unit 1100 shown in FIG. 49 to FIG. 51 will beexplained. FIG. 52 is an exploded perspective view of the atomizing unit1100 from which the first cover 1106 and the second cover 1107 have beenremoved. FIG. 53 is a cross-section view of the atomizing unit 1100. InFIG. 53, for convenience of explanation, the first liquid storage unit1200A and the second liquid storage unit 1200B are shown. As shown inFIG. 52, the atomizing unit 1100 comprises a base member 1108, a PCBboard 1109, a piezoelectric element substrate 1031 comprising a pair ofinterlocking comb-shaped metallic electrodes 1033, a pair of guide walls1711A and 1711B, and a top cover 1710. An adhesive sheet 1110 ispositioned between the base member 1108 and the PCB board 1109, so thatthe position of the PCB board 1109 relative to the base member 1108 isfixed, and leaking of the first liquid and the second liquid issuppressed.

As shown in FIG. 53, the piezoelectric element substrate 1031 ispositioned on a top surface of the PCB board 1109. A heat sink structure1035 similar to the heat sink structure 35 shown in FIG. 3 and FIG. 4 ispositioned on a rear surface of the piezoelectric element substrate1031. Note that it is possible to adopt the heat sink structure shown inFIGS. 39-41 in place of the heat sink structure 1035.

Further, the piezoelectric element substrate 1031 comprises a pair ofedges 1031A and 1031B which are opposite to each other. The guide wall1711A is positioned at the edge 1031A side, and the guide wall 1711B ispositioned at the edge 1031B side. The guide walls 1711A and 1711Bcomprise penetrated apertures 1713A and 1713B, which extend between thetop surface and the bottom surface, respectively. Further, the guidewalls 1711A and 1711B comprise concave parts 1714A and 1714Bcommunicating with the penetrated apertures 1713A and 1713B,respectively. As shown in FIG. 53, the first liquid storage unit 1200Aand the second liquid storage unit 1200B are connected to the bottomsurfaces of the guide walls 1711A and 1711B, respectively. The liquids(a first liquid and a second liquid) supplied by syringe pumps from thefirst liquid storage unit 1200A and the second liquid storage unit 1200Bpass through the penetrated apertures 1713A and 1713B from a lower sideto an upper side and arrive at the concave parts 1714A and 1714B,respectively. The liquids, which have arrived at the concave parts 1714Aand 1714B, arrive at the edges 1031A and 1031B, and are atomized byenergy in the pair of interlocking comb-shaped metallic electrodes 1033.That is, the syringe pumps are constructed to supply the first liquidand the second liquid to the edges 1031A and 1031B of the piezoelectricelement substrate 1031, respectively.

Further, the atomizing unit 1100 comprises a seal member 1111. The sealmember 1111 as a whole has an approximately ring shape, and is incontact with the top surfaces of the guide walls 1711A and 1711B and thetop surface of the piezoelectric element substrate 1031. As a result,the liquids that arrived at the concave parts 1714A and 1714B iscontrolled in such a manner that liquids do not flow to the outside ofthe guide walls 1711A and 1711B and the piezoelectric element substrate1031.

The atomizing unit 1100 comprises a pair of electric contacts 1032A and1032B which electrically connect contacts formed on the PCB board 1109with the pair of interlocking comb-shaped metallic electrodes 1033.Further, the atomizing unit 1100 comprises sensors 1070 for detectingliquid. In the example shown in FIG. 52, the sensor 1070 is an electricconductivity sensor. The function of the sensor 1070 is similar to thefunction of sensor 71 shown in FIG. 21. Also, the sensor for detectingthe liquid is not limited to the above, and it is possible to adopt theemitter/receiver sensor or the capacitive sensor shown in FIGS. 22-25.

As shown in FIG. 52 and FIG. 53, the top cover 1710 comprises, at acenter part thereof, an opening part 1710 a through which aerosolpasses, and is arranged to cover the guide walls 1711A and 1711B, thePCB board 1109, and the piezoelectric element substrate 1031, fromabove. Also, an O-ring 1113 is arranged between a periphery at the sidepart of the top cover 1710 and the first cover 1106.

Further, as shown in FIG. 53, the opening part 1710 a of the top cover1710 is positioned above the pair of interlocking comb-shaped metallicelectrodes 1033 and the pair of edges 1031A and 1031B of thepiezoelectric element substrate 1031. Thus, the aerosol from the firstliquid and the aerosol from the second liquid, which are generated bythe pair of edges 1031A and 1031B, can flow to the outside of the topcover 1710. Also, as shown in the figure, the first cover 1106 isarranged to cover the front surface side of the piezoelectric elementsubstrate 1031. The first opening part 1102 and the second opening part1104 of the first cover 1106 are positioned right above the edges 1031Aand 1031B of the piezoelectric element substrate 1031, respectively.Thus, the aerosol from the first liquid and the aerosol from the secondliquid, which are generated by the edges 1031A and 1031B, respectively,can pass through the first opening part 1102 and the second opening part1104, respectively. Accordingly, the first opening part 1102 of thefirst cover 1106 can emit the aerosol from the first liquid mainly, andthe second opening part 1104 can emit the aerosol from the second liquidmainly.

Further, as shown in FIG. 53, the first cover 1106 is arranged in such amanner that it covers the part right above the disposition portion,where the pair of interlocking comb-shaped metallic electrodes 1033 ispositioned, and is not to be in contact with the pair of interlockingcomb-shaped metallic electrodes 1033. Thus, the aerosol generated by theedges 1031A and 1031B is made to be in contact with the pair ofinterlocking comb-shaped metallic electrodes 1033, so that degradationof the pair of interlocking comb-shaped metallic electrodes 1033 can besuppressed, and propagation of a SAW by the pair of interlockingcomb-shaped metallic electrodes 1033 cannot be prevented. A gap betweenthe first cover 1106 and the piezoelectric element substrate 1031 may beapproximately several microns, for example. If the gap is that explainedabove, degradation of the pair of interlocking comb-shaped metallicelectrodes 33 can be suppressed sufficiently.

Next, the mouthpiece 1001D shown in FIG. 49 to FIG. 51 will beexplained. FIG. 54 is a cross-section view of the mouthpiece 1001D. Themouthpiece 1001D comprises a first pipeline 1016 which comprises atleast a part which is curved, a second pipeline 1018 which isapproximately straight, and a third pipe line 1020. As would beunderstood based on FIG. 50, the first pipeline 1016 communicates withthe first opening part 1102 of the first cover 1106, and the secondpipeline 1018 communicates with the second opening part 1104. That is,the first pipe line 1016 defines a first flow path 1016 a through whichthe first aerosol, which is generated by atomizing the first liquid,passes mainly. Also, the second pipe line 1018 defines a second flowpath 1018 a through which the second aerosol, which is generated byatomizing the second liquid, passes mainly. Also, regarding a third flowpath 1020 a which is defined by the third pipe line 1020, the firstaerosol and the second aerosol flow into each other in it and passthrough it. A first air inlet 1016 b is formed on a side surface of thefirst pipe line 1016, and a second air inlet 1018 b is formed on a sidesurface of the second pipe line 1018. As a result of inhaling action bya user, air flows into the first flow path 1016 a and the second flowpath 1018 a from the first air inlet 1016 b and the second air inlet.

Regarding the case that the first liquid includes nicotine and water,and that the first liquid is atomized by the SAW generated by the pairof interlocking comb-shaped metallic electrodes 1033, it has been knownthat peaks in diameter distribution of particles included in the aerosolappear at a point near 10 microns (hereinafter, coarse particles) and apoint in submicron (hereinafter, submicron particles), as shown by theexperimental result shown in FIG. 48. According to the mouthpiece 1001Dshown in FIG. 54, the aerosol including coarse particles, in the aerosolpassing through the first flow path 1016 a, collides with a wall surfaceof the first pipe line 1016 and is trapped thereby. Thus, the aerosolincluding coarse particles is eliminated from the aerosol passingthrough the first flow path 1016 a, so that the aerosol includingparticles having desired particle sizes can be supplied to the mouth ofthe user. For holding the collided particles in the aerosol, it ispreferable that the wall surface of the first pipe line 1016 is providedwith porous material such as a fibrous packed bed, a granular packedbed, a sponge, a sintered body, and so on, or the wall surface itself isformed by use of porous material.

Also, regarding the case that the second liquid includes flavorcomponents, and that the second liquid is atomized by the SAW generatedby the pair of interlocking comb-shaped metallic electrodes 1033, it hasbeen known that a peak in diameter distribution of particles included inthe aerosol appears at a point near 10 microns. According to themouthpiece 1001D shown in FIG. 54, each of the second pipe line 1018defining the second flow path 1018 a and the third pipe line 1020defining the third flow path 1020 a is formed to have an approximatelystraight shape. Thus, even if the particles of the aerosol generatedfrom the second liquid are coarse particles, trapping of aerosol by eachof wall surfaces of the second pipe line 1018 and the third pipe line1020 can be suppressed.

FIG. 55 is a side cross-section view showing another example of themouthpiece 1001D. The mouthpiece 1001D shown in FIG. 55 is different,when compared with the mouthpiece 1001D shown in FIG. 54, in the pointthat it comprises an air inlet 1022 communicating with the first flowpath 1016 a. In the mouthpiece 1001D shown in FIG. 55, the firstpipeline 1016 also comprises at least a part which is curved, and thesecond pipeline 1018 is also formed to have an approximately straightshape. Thus, the aerosol including coarse particles, in the aerosolpassing through the first flow path 1016 a, collides with a wall surfaceof the first pipe line 1016 and is trapped thereby. Also, even if theparticles of the aerosol generated from the second liquid are coarseparticles, trapping of aerosol by each of wall surfaces of the secondpipe line 1018 and the third pipe line 1020 can be suppressed. Forholding the collided particles in the aerosol, it is preferable that thewall surface of the first pipe line 1016 is provided with porousmaterial such as a fibrous packed bed, a granular packed bed, a sponge,a sintered body, and so on, or the wall surface itself is formed by useof porous material.

FIG. 56 is a perspective view showing a further example of themouthpiece 1001D. As shown in FIG. 56, the mouthpiece 1001D comprises abase part 1024 which is connected to the atomizing unit 1100 shown inFIG. 51 and so on, an air flow path part 1026 extending upwardly fromthe base part 1024, a separation part 1028 connected to the air flowpath part 1026, and an air outlet 1030. In the air flow path part 1026,an air inlet 1024A is formed for supplying air to an air flow path,which is not shown in the figure, of the air flow path part 1026.

The mouthpiece 1001D shown in FIG. 56 comprises a flow path in which theaerosol flown into the mouthpiece 1001D as a result of inhaling actionperformed by a user swirls while the aerosol passes through the flowpath, and is guided to the air outlet 1030. Specifically, air flowing infrom the air inlet 1024A during inhaling action performed by a usertakes therein the aerosol generated in the atomizing unit 1100, andarrives at the separation part 1028 via an air flow path, which is notshown in the figure, in the air flow path part 1026. Note that the firstaerosol, which is generated in the atomizing unit 1100 from the firstliquid may pass through the air flow path, which is not shown in thefigure, in the air flow path part 1026. In the separation part 1028,aerosol including coarse particles is trapped by swirling the aerosol,and aerosol including submicron particles flows out of the air outlet1030.

Further, the mouthpiece 1001D shown in FIG. 56 comprises the second pipeline 1018 through which the second aerosol, which is generated in theatomizing unit 1100 from the second liquid, may pass through. In thepresent modified example, the second pipe line 1018 extends, in anorthogonal direction, from the base part 1024. The second pipe line 1018is in fluid communication with the air outlet 1030, and aerosolincluding submicron particles, in the first aerosol, flows into thesecond pipe line 1018 from the air outlet 1030. The third pipe line 1020is that extending from the second pipe line 1018, and aerosol includingsubmicron particles, in the first aerosol, and the second aerosol passthrough the third pipe line 1020.

FIG. 57 is a schematic drawing of the mouthpiece 1001D wherein crosssections of the separation part 1028 and the air outlet 1030 shown inFIG. 56 are shown. The separation part 1028 comprises a cone part 1032which communicates with an air flow path 1026A of an air flow path part1026, a trap part 1034 which communicates with a tip part (asmaller-diameter side) of the cone part 1032, and an outflow part 1036which communicates with a rear end part (a larger-diameter side) of thecone part 1032. Aerosol flowing into the separation part 1028 from theair flow path 1026A swirls in the cone part 1032. At that time, aerosolincluding coarse particles is separated from the flow of air, trapped bya wall surface of the cone part 1032, and the trapped liquid is finallydropped into the trap part 1034 and held therein. On the other hand,aerosol including submicron particles does not adhere to the wallsurface of the cone part 1032 even if the aerosol is made to swirl, andflows into the second pipe line 1018 from the air outlet 1030 along withthe flow of air.

The mouthpiece 1001D shown in each of FIG. 54 to FIG. 56 may be providedwith at least one of the impactor 721 explained in relation to FIG. 46and the filter 725 explained in relation to FIG. 47 (each of whichcorresponds to an example of a trap member), in an appropriate manner.Then, coarse particles can be trapped in a more appropriate manner. Itis preferable that the impactor 721 is formed by use of porous materialsuch as a fibrous packed bed, a granular packed bed, a sponge, asintered body, and so on, for holding collided particles of aerosol.

FIG. 58 is a side cross-section view showing a still further example ofthe mouthpiece 1001D. FIG. 59 is a schematic side view showing the flowof air passing through the mouthpiece 1001D shown in FIG. 58. In FIG.59, the flow of air flowing in form a first air inlet 1016 b and asecond air inlet 1018 b is shown by use of an arrow. Similarly to themouthpiece 1001D shown in FIG. 54, the mouthpiece 1001D shown in FIG. 58and FIG. 59 comprises a first pipeline 1016 which comprises at least apart which is curved, a second pipeline 1018 which is approximatelystraight, and a third pipe line 1020. The first pipeline 1016communicates with the first opening part 1102 of the first cover 1106shown in FIG. 51, and the second pipeline 1018 communicates with thesecond opening part 1104. That is, the first pipe line 1016 defines afirst flow path 1016 a through which the first aerosol, which isgenerated by atomizing the first liquid, passes mainly. Also, the secondpipe line 1018 defines a second flow path 1018 a through which thesecond aerosol, which is generated by atomizing the second liquid,passes mainly. Also, regarding a third flow path 1020 a which is definedby the third pipe line 1020, the first aerosol and the second aerosolflow into each other in it and pass through it.

Further, the first flow path 1016 a in the mouthpiece 1001D shown inFIG. 58 and FIG. 59 is provided with an air flow accelerating member1037 and a trap member 1038 positioned at a downstream side of the airflow accelerating member 1037. The air flow accelerating member 1037 canreduce the flow path of the first flow path 1016 a, so that the flowvelocity of the first aerosol flowing toward the trap member 1038 can beincreased. The trap member 1038 is arranged at position whereat thefirst aerosol passed through the air flow accelerating member 1037collides, and to have a gap in terms of a cross section of the firstflow path 1016 a. In the example shown in the figure, the air flowaccelerating member 1037 is formed by use of a porous fibrous layerfilter having a through hole at the center thereof (a center hallfilter) or the like, and the trap member 1038 is formed by use of asolid porous fibrous layer filter (a super slim filter) or the like.

The second flow path 1018 a is provided with an air flow acceleratingmember 1039 which has a hole at the center part thereof. For example,the air flow accelerating member 1039 lies along the whole length of thesecond flow path 1018 a, and has an inner diameter larger than that ofthe air flow accelerating member 1037.

As shown by use of the arrow in FIG. 59, the air flowing in from thefirst air inlet 1016 b (not shown in FIG. 58) takes therein the firstaerosol from the first opening part 1102 shown in FIG. 51, and flowsinto the first flow path 1016 a. The air flowing in from the second airinlet 1018 b takes therein the second aerosol from the second openingpart 1104 shown in FIG. 51, and flows into the second flow path 1018 a.

A part of aerosol including coarse particles, in the first aerosol flowninto the first flow path 1016 a, is trapped by an inner surface of theair flow accelerating member 1037 when the aerosol passes through theair flow accelerating member 1037 which is formed by use of a filter.Also, the flow velocity of the first aerosol passed through the air flowaccelerating member 1037 is increased by the air flow acceleratingmember 1037, and the first aerosol collides with the trap member 1038.As a result, aerosol including coarse particles, in the first aerosol,is trapped by the trap member 1038, and, on the other hand, aerosolincluding submicron particles is not trapped by the trap member 1038, sothat it passes through the gap between the trap member 1038 and the wallsurface of the first pipe line 1016, and arrives at the third flow path1020 a. By increasing the flow velocity of the first aerosol by use ofthe air flow accelerating member 1037, efficiency of inertial trappingof aerosol, which includes coarse particles, in the trap member 1038 canbe improved.

As shown in the figure, since the second pipe line 1018 is formed tohave an approximately straight shape, trapping of the second aerosol,which includes coarse particles and flows into the second flow path 1018a, at a wall surface of the second pipeline 1018 (inner wall of the airflow accelerating member 1039) is suppressed, so that the second aerosolcan arrive at the third pipe line 1020. Note that the air flowaccelerating member 1037, the trap member 1038, and the air flowaccelerating member 1039 may be formed by use of porous material such asa fibrous packed bed, a granular packed bed, a sponge, a sintered body,and so on.

FIG. 60 is a side cross-section view showing a still further example ofthe mouthpiece 1101D. FIG. 61 is a schematic side view showing the flowof air passing through the mouthpiece shown in FIG. 60. The mouthpiece1001D shown in FIG. 60 and FIG. 61 is different, when compared with themouthpiece 1001D shown in FIG. 58 and FIG. 59, in the point that the airinlet for supplying air to the mouthpiece 1001D of the former isdifferent from that of the latter. Specifically, the mouthpiece 1001Dshown in FIG. 60 and FIG. 61 comprises an air inlet 1025 positionedbetween a first pipe line 1016 and a second pipe line 1018, instead ofthe first air inlet 1016 b and the second air inlet 1018 b.

The air inlet 1025 goes through the mouthpiece 1001D from a surface at afront side to a surface at a rear side of the mouthpiece 1001D, when thesheet showing FIG. 61 is viewed from the front. Also, as shown in FIG.61, the air inlet 1025 communicates with the first flow path 1016 a ofthe first pile line 1016 and the second flow path 1018 a of the secondflow path 1018. A part of the air flowing in from the air inlet 1025takes therein the first aerosol from the first opening part 1102 shownin FIG. 51, and flows into the first flow path 1016 a. Also, theremaining part of the air flowing in from the air inlet 1025 takestherein the second aerosol from the second opening part 1104 shown inFIG. 51, and flows into the second flow path 1018 a. Further, in thecase of the present example, an opening which is different from thefirst opening part 1102 and the second opening part 1104 may be formedon the first cover 1106 shown in FIG. 51 and FIG. 53, and air taken fromthe air inlet 1025 may be made to be flown into the inside of the firstcover 1106, made to pass on the surface of the IDT (the pair ofinterlocking comb-shaped metallic electrodes 1033), and, thereafter,made to flow through the first opening part 1102 and the second openingpart 1104. By causing the air to flow as explained above, adhesion ofthe aerosol, which is generated by the edge 1031A and the edge 1031B, tothe IDT can be more reliably prevented. Note that, the flow of airexplained above is not limited to that in the case of the mouthpiece1001D shown in FIG. 61, and it may be adopted in other mouthpieces1001D.

The mouthpieces 1001D shown in FIG. 54 to FIG. 61 are explained as thosehaving the third pipe lines 1020; however, the constructions thereof arenot limited to those explained above. That is, each of the mouthpieces1001D shown in FIG. 54 to FIG. 61 may be constructed in such a mannerthat it does not comprise the third pipe line 1020, and the firstaerosol passing through the first pipe line 1016 and the second aerosolpassing through the second pipe line 1018 arrive at the mouth of a userindependently from each other. Further, regarding the twenty-fourthmodification, although it is explained that the second liquid isatomized by use of energy of a surface acoustic wave in the IDT, theconstruction is not limited to the above, and the second liquid may beatomized by use of another appropriate method such as that using anexisting mesh nebulizer or the like. Further, the first cover 1106 andthe second cover 1107 shown in FIG. 51 to FIG. 53 may be formed by useof metal, for suppressing emission of EMC.

<Experiment 1>

An experiment for measuring diameter distribution with respect toaerosol passed through the first flow path 1016 a and the third flowpath 1020 a in the mouthpiece 1001D shown in FIG. 58 and FIG. 59 wasconducted. In the experiment, the flow rate of the aerosol was set to 55ml/3 s, and a solution including 96 wt % of water, 2 wt % of malic acid,and 2 wt % of nicotine was adopted as the aerosol source. Spraytechwhich is available from Malvern corporation was used as the measurementdevice. Further, an experiment in which the air flow accelerating member1037 and the trap member 1038 are not used, an experiment in which theair flow accelerating member 1037 having an inner diameter of 2.0 mm isused, and an experiment in which the air flow accelerating member 1037having an inner diameter of 3.2 mm is used, in the mouthpiece 1001, wereconducted.

FIG. 62 is a graph showing a result of measurement of diameterdistribution with respect to aerosol in experiment 1. Note that thevertical axis in FIG. 62 shows weight distribution, that is a result oftransformation from volume distribution, when it is assumed that anintegrated value of volume distribution of all aerosol particlediameters corresponds to weight of the aerosol inhaled by a singleinhaling action. Note that the weight of the aerosol inhaled by a singleinhaling action was evaluated by trapping, by a filter, aerosoloutputted when the inhaling action is performed in such a manner that aquantity of 55 ml is inhaled during a period of 3 seconds with constantinhaling velocity, and calculating a difference between the weightbefore the inhaling action and the weight after the inhaling action. Asshown in FIG. 62, in the case that the air flow accelerating member 1037and the trap member 1038 are not used in the mouthpiece 1001D, a peak ofthe diameter distribution appeared at a point near 10 microns. On theother hand, in each of the case that the trap member 1038 and the airflow accelerating member 1037 having an inner diameter of 2.0 mm is usedand the case that the trap member 1038 and the air flow acceleratingmember 1037 having an inner diameter of 3.2 mm is used, distribution ofparticle diameters around 10 microns disappeared. More specifically, inthe case that the trap member 1038 and the air flow accelerating member1037 having an inner diameter of 2.0 mm is used, almost all diameterdistribution of 2 microns or more disappeared; and in the case that thetrap member 1038 and the air flow accelerating member 1037 having aninner diameter of 3.2 mm is used, almost all diameter distribution of 5microns or more disappeared. On the other hand, diameter distribution ofsubmicron particles in each case is not very different from those ofother cases. Based on the above result of the experiment, it can beunderstood that aerosol including coarse particles is trapped, andsubmicron particles are allowed to arrive at the third flow path 1020 a,in the case that the trap member 1038 and the air flow acceleratingmember 1037 are used.

<Experiment 2>

An experiment for verifying degrees of discomfort in a throat, whenaerosol passed through the first flow path 1016 a and the third flowpath 2010 a in the mouthpiece 1001D shown in FIG. 58 and FIG. 59 wasinhaled, was conducted. In the experiment, a solution including 96 wt %of water, 2 wt % of malic acid, and 2 wt % of nicotine was adopted asthe aerosol source; and degrees of discomfort in a throat with respectto each person on a panel including five people, when the personperformed inhaling action by use of the mouthpiece 1001D, were verified.Also, similarly to the case of experiment 1, an experiment in which theair flow accelerating member 1037 and the trap member 1038 are not used,an experiment in which the air flow accelerating member 1037 having aninner diameter of 2.0 mm is used, and an experiment in which the airflow accelerating member 1037 having an inner diameter of 3.2 mm isused, in the mouthpiece 1001, were conducted.

FIG. 63 shows a graph and an evaluation sheet showing degrees ofdiscomfort in the throat. Regarding discomfort in the throat, thestrength of discomfort in the throat, that was felt by each person onthe panel when the person inhaled aerosol, was evaluated by use of theevaluation sheet shown in FIG. 63. Specifically, discomfort in thethroat in the case that each of the five people on the panel inhaledaerosol by use of the mouthpiece 1101D which uses neither the air flowaccelerating member 1037 nor the trap member 1038 was evaluated, anddiscomfort in the throat with respect to each of the other examples wasalso evaluated. In addition to the positions on the evaluation sheetwhere numbers are written, each person on the panel can enter arecording mark on any position, such as a position between the numbers 2and 3, for example. In analysis of the result, positions of recordedmarks are measured by use of a ruler, and are converted to numericalvalues. Each error bar in the graph in FIG. 63 shows a confidenceinterval with respect to a population mean when the confidence level is95%.

Note that, in the experiment, a solution including 2 wt % of nicotine, 2wt % of malic acid, and 96 wt % of water was used, and it was atomizedby supplying electric power of 11 W with a resonant frequency of 23.9MHz. The parts shown in FIGS. 60 and 61 were used in the mouthpiece1101D. The quantity of the solution to be supplied during atomizationwas set to 5 mg/sec, and each subject inhaled the atomized aerosol forarbitrary length of time, and performed evaluation with respect to thedegree of discomfort felt during the time.

As shown by the graph in FIG. 63, in each of the case that the air flowaccelerating member 1037 having an inner diameter of 2.0 mm is used andthe case that the air flow accelerating member 1037 having an innerdiameter of 3.2 mm is used, the degree of discomfort in the throat wassignificantly lowered, compared with the case that air flow acceleratingmember 1037 and the trap member 1038 were not used in the mouthpiece1101D; thus, it can be stated that the above two cases are preferable interms of feeling of fragrance inhaling taste.

Regarding the case of FIG. 63, note that, in the case that the air flowaccelerating member 1037 and the trap member 1038 are used, the quantityof nicotine inhaled per unit time is reduced, compared with the casethat the air flow accelerating member 1037 and the trap member 1038 arenot used. For evaluating the effect due to the above matter,concentration of nicotine in the solution, which was used, was adjustedin such a manner that the quantity of nicotine inhaled per unit time wasset to be the same, and evaluation was performed; however, as a result,the tendency shown in FIG. 63 was not changed (not shown in the figure).That is, the size of the particle mainly contributes mainly to thedegree of discomfort in the throat, and the degree of discomfort in thethroat can be lowered by reducing coarse particles.

As explained above, according to experiment 1, aerosol including coarseparticles is trapped, and submicron particles are allowed to arrive atthe third flow path 1020 a, in the case that air flow acceleratingmember 1037 and the trap member 1038 are used. Accordingly, inexperiment 2, it can be understood that, in the case that air flowaccelerating member 1037 and the trap member 1038 are used, aerosolincluding coarse particles is trapped, and submicron particles areallowed to arrive at the third flow path 1020 a, thus, arrive at themouth of a user. Also, in experiment 2, in the case that air flowaccelerating member 1037 and the trap member 1038 are used, discomfortin the throat can be remarkably reduced, and desirable fragranceinhaling taste can be obtained. That is, it can be stated that, by usingthe flow accelerating member 1037 and the trap member 1038 in themouthpiece 1001D, aerosol including coarse particles is trapped, and, asa result, discomfort in the throat is remarkably reduced.

In general, it has been known that the size of a particle emitted from acigarette when it is burned is approximately 0.2 microns. On the otherhand, as explained above, the aerosol generated by the atomizing unit1100 relating to the twenty-fourth modification includes coarseparticles, each having the size of approximately 10 microns, in additionto submicron particles. Thus, by adopting the mouthpiece 1001D shown inFIG. 58 in the unit 1000 relating to the twenty-fourth modification,submicron particles are allowed to arrive at the mouth of a user whilethe coarse particles are remarkably reduced. As a result, fragranceinhaling taste similar to that obtainable from a burned cigarette can beobtained. Note that since the mouthpieces 1001D shown in FIG. 54 to FIG.57 can also deliver submicron particles into the mouth of a user whilereducing the coarse particles, the mouthpieces can provide fragranceinhaling taste similar to that provided by the mouthpiece 1001D shown inFIG. 58.

[Twenty-Fifth Modification]

Regarding the twenty-fifth modification, a sensor 1070 for detecting aliquid supplied to the edges 1031A and 1031B in the piezoelectricelement substrate 1031 shown in FIG. 52 will be explained. For example,based on result of detection by the sensor 1070, the controller 400shown in FIG. 1 may drive the motors 1208A and 1208B which are liquidsuppliers and are shown in FIG. 50, and control the supply speeds of theliquids and the supply quantities of the liquids that are supplied fromthe first liquid storage unit 1200A and the second liquid storage unit1200B to the edges 1031A and 1031B, respectively. A sufficient atomizingamount cannot be obtained in the case that the quantities of liquidssupplied to the edges 1031A and 1031B are small; and the particlediameters in atomized aerosol become large in the case that thequantities of liquids supplied to the edges 1031A and 1031B are large.Specifically, at that time, aerosol which includes extra-largeparticles, each of which is larger than a coarse particle and has adiameter of approximately 100 microns, and particles, each of which hasa diameter larger than that of an extra-large particle, is generated.Thus, by controlling operation of the liquid suppliers by the controller400 based on result of detection by the sensor 1070, certain quantitiesof liquids can be supplied to the edges 1031A and 1031B in thepiezoelectric element substrate 1031. As a result, a sufficientatomizing amount can be realized, and generation of aerosol having aparticle diameter larger than that of a coarse particle can beprevented.

FIG. 64 is an enlarged view of a part extracted from the atomizing unit1100 shown in FIG. 52. Specifically, FIG. 64 illustrates the PCB board1109, the piezoelectric element substrate 1031 comprising the pair ofinterlocking comb-shaped metallic electrodes 1033, the guide wall 1711A,the seal member 1111, and the sensor 1070 in the atomizing unit 1100shown in FIG. 52.

In FIG. 64, the sensor 1070 comprises a pair of sensor electrodes(detection part) 1070A and 1070B which are opposite to each other. Thesensor electrodes 1070A and 1070B are constructed by use of a metal suchas gold-plated copper, for example. Also, the sensor electrodes 1070Aand 1070B are attached to the PCB board 1109, and electrically connectedto contacts formed on the PCB board 1109. In this regard, the sensorelectrodes 1070A and 1070B are positioned above the piezoelectricelement substrate 1031, with the seal member 1111 positioned between thesensor electrodes 1070A and 1070B and the piezoelectric elementsubstrate 1031. For example, the sensor electrodes 1070A and 1070B arepositioned in such a manner that they are separated by 0.1 mm (±0.05 mm)from the surface of the piezoelectric element substrate 1031. In thecase that the sensor electrodes 1070A and 1070B are positioned on thesurface of the piezoelectric element substrate 1031, there are risksthat the sensor electrodes 1070A and 1070B may peel off, and relativepositions of the sensor electrodes 1070A and 1070B may shift, due tovibration caused by a SAW that propagates through the piezoelectricelement substrate 1031. Thus, by separating the sensor electrodes 1070Aand 1070B from the surface of the piezoelectric element substrate 1031,peeling off of the sensor electrodes 1070A and 1070B and shifting ofrelative positions of the sensor electrodes 1070A and 1070B can beprevented, and accurate result of detection can be obtained.

The sensor electrode 1070A comprises a base part 1071A which has arectangular shape and has one end side electrically connected to acontact formed on the PCB board 1109, and a convex part 1072A whichprojects toward the sensor electrode 1070B from the other end side ofthe base part 1071A. On the other hand, the sensor electrode 1070Bcomprises a base part 1071B which has a rectangular shape and has oneend side electrically connected to a contact formed on the PCB board1109, and a convex part 1072B which projects toward the sensor electrode1070A from the other end side of the base part 1071B. Note that each ofthe base parts 1071A and 1071B may have a shape other than a rectangularshape. The convex parts 1072A and 1072B are positioned adjacent to theedge 1031A to which liquid is supplied, and are electrically connectedby the liquid supplied from the edge 1031A. The sensor 1070 outputs, asdetection result, the conductivity of the electric signal correspondingto the quantity of the liquid between the convex part 1072A and theconvex part 1072B. The conductivity of the electric signal outputtedfrom the sensor 1070 becomes large as the quantity of the liquidsupplied to the edge 1031A becomes large. Thus, it is possible to judge,based on the magnitude of the conductivity of the electric signal, thestate that an appropriate quantity of the liquid is supplied to the edge1031A, the state that an excessive quantity of the liquid is supplied tothe edge 1031A, and the state that the quantity of the liquid suppliedto the edge 1031A is insufficient.

In the case that the controller 400 has judged, based on theconductivity of the electric signal outputted from the sensor 1070, thatan excessive quantity of the liquid has been supplied to the edge 1031A,it drives the motor 1208A to reduce the liquid supply speed and/or theliquid supply quantity of the liquid supplied from the first liquidstorage unit 1200A to the edge 1031A. Further, in the case that thecontroller 400 has judged, based on the conductivity of the electricsignal outputted from the sensor 1070, that the quantity of the liquidsupplied to the edge 1031A is insufficient, it drives the motor 1208A toincrease the liquid supply speed and/or the liquid supply quantity ofthe liquid supplied from the first liquid storage unit 1200A to the edge1031A. As a result, a certain appropriate quantity of the liquid can besupplied to the edge 1031A, so that a sufficient atomizing amount can berealized, and generation of aerosol having particle diameters largerthan those of coarse particles can be prevented. Note that, although theedge 1031A side is extracted and shown in FIG. 64, the edge 1031B sidealso has a construction similar to that of the edge 1031A side, and thecontroller 400 drives, based on detection result from the sensor 1070,the motor 1208B in a manner similar to that in the case of the edge1031A side.

Next, positional relationship between the piezoelectric elementsubstrate 1031 and the sensor electrodes 1070A and 1070B and positionalrelationship between the piezoelectric element substrate 1031 and theguide wall 1711A will be explained with reference to result ofexperiments. As shown in FIG. 64, it is defined herein that the spacebetween the top end of the convex part 1072A and the top end of theconvex part 1072B is C1; the space between the edge 1031A and the side,at the edge 1031A side, of each of the convex part 1072A and the convexpart 1072B is C2; and the space between the edge 1031A and the endsurface, at the edge 1031A side, of the guide wall 1711A is L1.

First, the atomizing amounts of aerosol generated in the atomizing unit1100 were measured, under a condition that the space C1 is set to 4 mm,the space L1 is set to 0.4 mm, and the space C2 is varied. Note that thespace C1 may be set in accordance with the output width of the SAW,i.e., the width that the aerosol is generated, to correspond to theoverlap length of the pair of interlocking comb-shaped metallicelectrodes 1033. In the measurement, electric power of 10 W was suppliedto the pair of interlocking comb-shaped metallic electrodes 1033, andthe atomizing amounts, when liquid for testing was atomized, weremeasured, under the state that the top cover 1710 has been removed. FIG.65 is a graph showing relationship between the space C2 and theatomizing amount. In FIG. 65, the horizontal axis represents the spaceC2 (mm), and the vertical axis represents an atomizing amount per asingle puff TPM/puff (mg). Note that, in the case that the space C2 is anegative value, it means that the convex part 1072A and the convex part1072B are positioned, across the edge 1031A, on the guide wall 1711A. Itcan be understood from FIG. 65 that the atomizing amount becomes themaximum at a point where the space C2 is around 0.15 mm. Thus, it isdesirable that the space C2 be set to 0.15 mm (±0.05 mm).

Next, the atomizing amounts of aerosol generated in the atomizing unit1100 were measured, under a condition that the space C1 is set to 4 mm,the space C2 is set to 0.15 mm, and the space L1 is varied. In themeasurement, electric power of 10 W was supplied to the pair ofinterlocking comb-shaped metallic electrodes 1033, and the atomizingamounts when liquid for testing was atomized were measured, under thestate that the top cover 1710 has been removed. FIG. 66 is a graphshowing relationship between the space L1 and the atomizing amount. InFIG. 66, the horizontal axis represents the space L1 (mm), and thevertical axis represents an atomizing amount TPM/puff (mg). It can beunderstood from FIG. 66 that the atomizing amount becomes the maximum inthe region where the space L1 is equal to or larger than 0.25 mm. Thus,it is desirable that the space L1 be set to equal to or larger than 0.25mm.

Note that, although the case that the sensor 1070 is an electricconductivity sensor has been explained with respect to the presentmodified example, the sensor is not limited to the above, and theemitter-receiver sensor or the capacitive sensor shown in FIGS. 22-25may be adopted as a sensor for detecting liquid.

[Twenty-Sixth Modification A]

In the following, a modified example 26A of the embodiment will beexplained. In the following, differences between embodiments will beexplained mainly.

Regarding the modified example 26A, amplitude of a voltage having a highfrequency (this is also referred to as a “high-frequency voltage” in thefollowing explanation of the modified example 26A) applied to the pairsof interlocking comb-shaped metallic electrodes 33 will be explained.

Specifically, in the modified example 26A, the controller 400periodically changes amplitude of a high-frequency voltage applied tothe pairs of interlocking comb-shaped metallic electrodes 33. In thecase that the amplitude of the high-frequency voltage is set to beconstant and is applied, power consumption becomes large, and, duethereto, the piezoelectric element substrate 31 may be overheated; thus,if a configuration for periodically changing the amplitude is adopted,power consumption can be reduced, and damage to the piezoelectricelement substrate 31, due to high temperature, can be avoided. Further,according the above configuration, it is possible to suppress scatteringby receiving a SAW of a droplet, as a bulk droplet, from liquid, whichis guided to the front surface 31F of the piezoelectric elementsubstrate 31. FIG. 67 is an example picture in which a droplet 3210scattered as a bulk droplet is photographed. Note that 3220 denotesminute particles, and 3230 denotes a droplet adhered to the frontsurface 31F of the piezoelectric element substrate 31 after it isscattered. By suppressing scattering of a bulk droplet, the liquid canbe used effectively, and stable atomization of aerosol can be realized.In detail, when a high voltage is being applied, aerosol is atomized byuse of a liquid at a side close to the pairs of interlocking comb-shapedmetallic electrodes 33 (the thin film part); and, when a low voltage isbeing applied, supply of the liquid to the thin film part, that isreduced as a result of atomization, is accelerated. As a result that theabove phenomena are repeated in a periodic manner, generation ofparticles having sizes larger than a predetermined size can besuppressed, and the quantity of atomization of minute particles can beincreased (Refer to FIG. 5 and explanations relating thereto, also.).Note that it is preferable to repeat application of a high voltage and alow voltage, i.e., it is preferable to repeat increasing and decreasingof amplitude of the high-frequency voltage at a frequency betweenapproximately 50 Hz-500 Hz, more preferably, at a frequency ofapproximately 100 Hz.

Periodic changing in the amplitude of the high-frequency voltage can berealized by defining the high-frequency voltage applied to the pairs ofinterlocking comb-shaped metallic electrodes 33 as a wave which is to bemodulated, and performing amplitude modulation based on a modulatingsignal having a predetermined waveform. The controller 400 may comprisea modulating signal generating circuit, a modulation circuit, and so on.

Alternatively, it is possible to realize periodic changing of theamplitude of the high-frequency voltage by use of the controller 400 insuch a manner that the amplitude of the high-frequency voltage appliedto the pairs of interlocking comb-shaped metallic electrodes 33 is madeto be a wave having a predetermined waveform. In such a case, it is notnecessary to include a modulating signal generating circuit, amodulation circuit, or the like in the controller 400.

For example, as shown in FIG. 68, the periodic amplitude of thehigh-frequency voltage, and the above modulating signal which is causesof such a periodic amplitude may draw a sine wave shape, may draw arectangular wave shape, may draw a triangular wave shape, or may draw asaw tooth wave shape. Especially, it is preferable that a high-frequencyvoltage be applied in such a manner that the periodic amplitude of thehigh-frequency voltage draws a rectangular wave shape. The controller400 can change the amplitude of the high-frequency voltage applied tothe pair of interlocking comb-shaped metallic electrodes 33 in such amanner that the change in the amplitude over time corresponds to theshape of a rectangular wave, by providing with, in an alternativemanner, a period during which the high-frequency voltage is applied anda period during which the high-frequency voltage is not applied.

In the case that a sine wave is used, the period of the sine wave may beset, by performing numerical calculation or performing an experiment,such that damage to the piezoelectric element substrate 31 due tooverheat at the time that the high-frequency voltage is applied to thepair of interlocking comb-shaped metallic electrodes 33 is prevented. Inaddition or alternatively, the period of the sine wave may be set, byperforming numerical calculation or performing an experiment, such thatgeneration of particles having sizes larger than a predetermined size inatomization is suppressed.

In the case that a rectangular wave is used, a duty ratio of therectangular wave may be set, by performing numerical calculation orperforming an experiment, such that damage to the piezoelectric elementsubstrate 31 due to high temperature is prevented, and/or generation, byatomization, of particles having particle sizes larger than apredetermined size is suppressed, when the high-frequency voltage isapplied to the pairs of interlocking comb-shaped metallic electrodes 33.

In the case that a triangular wave is used, a slope during an increasingstate and a slope during a decreasing state in the triangular wave maybe set, by performing numerical calculation or performing an experiment,such that damage to the piezoelectric element substrate 31 due to hightemperature is prevented, and/or generation, by atomization, ofparticles having particle sizes larger than a predetermined size issuppressed, when the high-frequency voltage is applied to the pairs ofinterlocking comb-shaped metallic electrodes 33.

Note that, in more general, the “slope during an increasing state” canbe specified by a ratio between amplitude and a length of a period (thiscorresponds to pSin+ in FIG. 68), during which a change occurs in afirst direction which is parallel the amplitude (for example, D1 in FIG.68), in a single period of the triangular wave. Also, in more general,the “slope during a decreasing state” can be specified by a ratiobetween the amplitude and a length of a period (this corresponds topSin− in FIG. 68), during which a change occurs in a second directionopposite to the first direction, in a single period of the triangularwave.

In the case that a saw tooth wave is used, a slope of the saw tooth wavemay be set, by performing numerical calculation or performing anexperiment, such that damage to the piezoelectric element substrate 31due to high temperature is prevented, and/or generation, by atomization,of particles having particle sizes larger than a predetermined size issuppressed, when the high-frequency voltage is applied to the pairs ofinterlocking comb-shaped metallic electrodes 33.

Note that, in more general, a “slope” of a saw tooth wave can bespecified by a ratio between a length of a single period of the sawtooth wave and amplitude thereof.

Note that, although the “droplet” scattered as a bulk droplet, which isexplained above, includes an extra-large particle having a particlediameter of approximately 100 microns which is larger than that of acoarse particle, and a particle having a particle diameter larger thanthat of an extra-large particle, the “droplet” is not limited to thoseexplained above. Accordingly, the “predetermine size” with respect tothe above explained “particle larger than a predetermined size” may be100 microns, for example.

At least a part of the controller 400 according to the modified example26A may be realized by a processor. For example, the controller 400 maycomprise a processor and a memory which stores a program, and theprogram may be that causing the processor to function as at least a partof the controller 400 according to the modified example 26A.

[Twenty-Sixth Modification B]

In the following, a modified example 26B of the embodiment will beexplained. The modified example 26B is a modified version of themodified example 26A; and, in the following, differences from themodified example 26A will be explained mainly.

In the modified example 26A, the amplitude of the high-frequency voltageapplied to the pairs of interlocking comb-shaped metallic electrodes 33is periodically changed; on the other hand, in the modified example 26B,the frequency of the high-frequency voltage applied to the pairs ofinterlocking comb-shaped metallic electrodes 33 is periodically changed.According to the above configuration, it is possible to suppressscattering by receiving a SAW of a droplet, as a bulk droplet, fromliquid, which is guided to the front surface 31F of the piezoelectricelement substrate 31. By the above configuration, the liquid can be usedeffectively, and stable atomization of aerosol can be realized. Indetail, when a high-frequency voltage having a frequency relativelyclose to a resonant frequency is being applied, aerosol is atomized byuse of a liquid at a side close to the pairs of interlocking comb-shapedmetallic electrodes 33 (the thin film part); and, when a high-frequencyvoltage having a frequency relatively far from the resonant frequency isbeing applied, supply of the liquid to the thin film part, that isreduced as a result of atomization, is accelerated. As a result that theabove phenomena are repeated in a periodic manner, generation ofparticles having sizes larger than a predetermined size can besuppressed, and the quantity of atomization of minute particles can beincreased (Refer to FIG. 5 and explanations relating thereto, also.).Note that it is preferable to repeat frequency changing of thehigh-frequency voltage at a frequency between approximately 50 Hz-500Hz, more preferably, at a frequency of approximately 100 Hz.

Periodic changing in the frequency of the high-frequency voltage can berealized by defining the high-frequency voltage applied to the pairs ofinterlocking comb-shaped metallic electrodes 33 as a wave which is to bemodulated, and performing frequency modulation based on a modulatingsignal having a predetermined waveform. The controller 400 may comprisea modulating signal generating circuit, a modulation circuit, and so on.The modulating signal may draw a sine wave shape, may draw a rectangularwave shape, may draw a triangular wave shape, or may draw a saw toothwave shape.

In the case that a sine wave is used, the period of the sine wave may beset, by performing numerical calculation or performing an experiment,such that generation, by atomization, of particles having sizes largerthan the above predetermined size is suppressed.

In the case that a rectangular wave is used, a duty ratio of therectangular wave may be set, by performing numerical calculation orperforming an experiment, such that generation, by atomization, ofparticles having sizes larger than the above predetermined size issuppressed.

In the case that a triangular wave is used, a slope during an increasingstate and a slope during a decreasing state in the triangular wave maybe set, by performing numerical calculation or performing an experiment,such that generation, by atomization, of particles having sizes largerthan the above predetermined size is suppressed.

In the case that a saw tooth wave is used, a slope of the saw tooth wavemay be set, by performing numerical calculation or performing anexperiment, such that generation, by atomization, of particles havingsizes larger than the above predetermined size is suppressed.

At least a part of the controller 400 according to the modified example26B may be realized by a processor. For example, the controller 400 maycomprise a processor and a memory which stores a program, and theprogram may be that causing the processor to function as at least a partof the controller 400 according to the modified example 26B.

[Twenty-Sixth Modification C]

A modified example 26C is a combination of the modified example 26A andthe modified example 26B. That is, in the modified example 26C, theamplitude and the frequency of the high-frequency voltage applied to thepairs of interlocking comb-shaped metallic electrodes 33 areperiodically changed. The period for changing the amplitude and theperiod for changing the frequency may be the same or different.

At least a part of the controller 400 according to the modified example26C may be realized by a processor. For example, the controller 400 maycomprise a processor and a memory which stores a program, and theprogram may be that causing the processor to function as at least a partof the controller 400 according to the modified example 26C.

[Twenty-Sixth Modification D]

In the following, a modified example 26D of the embodiment will beexplained. In the following, differences between embodiments will beexplained mainly.

Regarding the modified example 26D, relationship between a liquid supplyspeed (μl/sec) of liquid guided to the front surface 31F of thepiezoelectric element substrate 31 and output (W) of a SAW generated asa result of application of a high-frequency voltage to the pairs ofinterlocking comb-shaped metallic electrodes 33 will be explained.

First, as shown in FIG. 69, the controller 400 makes the output of theSAW gradually increase from time tStart, such that the output of the SAWreaches a desired level at time t2. The controller 400 makes the outputof the SAW be zero at time tEnd. On the other hand, the controller 400makes the liquid supply speed increase to a desired level at time t1.The controller 400 makes the liquid supply speed be zero at time tEnd.The time t1 may be that between the time tStart and the time t2.

Second, as shown in FIG. 70, the controller 400 makes the output of theSAW gradually increase, from time tStart, such that the output of theSAW reaches a desired level at time t2. The controller 400 makes theoutput of the SAW be zero at time tEnd. On the other hand, thecontroller 400 makes the liquid supply speed gradually increase, fromtime t1, such that the liquid supply speed reaches a desired level attime t3. The controller 400 makes the liquid supply speed be zero attime tEnd. The time t1 may be that between the time tStart and the timet2. The time t3 may be that after the time t2.

Note that the time tStart may be the timing when the start of a puffaction is detected by the sensor 300, or the timing when a button forperforming a puff action is pressed. The time tEnd may be the timingwhen the end of a puff action is detected by the sensor 300, or timingwhen a button for performing a puff action, which has been pressed, isreleased.

As shown in FIG. 69 and FIG. 70, the output of the SAW graduallyincreases form the time tStart, and increasing of the liquid supplyspeed is started at the time t1 that is after the time tStart; thus, inan initial stage for increasing the output (W) of the SAW, it ispossible to suppress scattering by receiving the SAW of a droplet havinga large diameter, i.e., a bulk droplet, from the liquid, which is guidedto the front surface 31F of the piezoelectric element substrate 31.Further, as shown in FIG. 70, by gradually increasing the liquid supplyspeed, scattering of a droplet having a large diameter, i.e., a bulkdroplet, can be suppressed.

Note that the modified example 26D deals with the problem that powerconsumption becomes large in the case that the amplitude of thehigh-frequency voltage is set to be constant. That is, in the modifiedexample 26D, the SAW output is zero at the time tStart, and it graduallyincreases to a desired level. This can be realized by changing theamplitude of the high-frequency voltage applied to the pairs ofinterlocking comb-shaped metallic electrodes 33 to that by which desiredSAW output is obtained. Thus, according to the modified example 26D,power consumption becomes smaller, compared with the case that ahigh-frequency voltage having constant amplitude is applied, such thatSAW output having a predetermined level is obtained from the point intime at the time tStart.

FIG. 71 is an example flow chart 3000A for realizing the above-explainedprocess. The respective steps included in the flow chart may be thoseexecuted by the controller 400.

Note that the flow chart 3000A corresponds to a single suction (puff)action, and a similar process may be performed with respect to eachsuction action. Accordingly, after completion of the process shown bythe flow chart 3000A, the process may be repeated immediately; thus, inthe flow chart 3000A, right after the process has reached “END,” theprocess may proceed to “START.” In such a case, the process shown by theflow chart 3000A forms a loop; and the loop is commenced from “START”when a predetermined signal (for example, a signal representing a powerON state) is received by the controller 400, and terminated when anotherpredetermined signal (for example, a signal representing a power OFFstate) is received by the controller 400.

3010A denotes a step for determining whether the start of a puff actionis detected. In the case that the start of a puff action is detected,the process proceeds to step 3020A, and, if not, step 3010A is repeated.Note that the above-explained time tStart may be a point of time whenthe start of a puff action is detected in the step.

3020A denotes a step for initializing parameters A and v, whichrepresent the amplitude of a high-frequency voltage applied to the pairsof interlocking comb-shaped metallic electrodes 33 and speed of supplyof liquid to the SAW module, more specifically, to the piezoelectricelement substrate 31, to have values of zeros, respectively.

3030A denotes a step for generating signals for applying ahigh-frequency voltage having amplitude of magnitude A to the pairs ofinterlocking comb-shaped metallic electrodes 33 and supplying liquidwith a liquid supply speed of magnitude v to the piezoelectric elementsubstrate 31. The above signals may be that which is to be sent to theatomizing unit 100.

3040A denotes a step for determining whether time t that has elapsedsince the start of the puff action has detected in step 3010A is equalto or longer than a first predetermined time, in other words, whetherthe first predetermined time has elapsed since the start of the puffaction has detected. If it is determined that the first predeterminedtime has elapsed, the process proceeds to step 3050A, and, if not, theprocess proceeds to step 3060A. The first predetermined time correspondsto the above-explained time t1 minus the time tStart.

3050A denotes a step for setting the parameter v to a predeterminedvalue. The predetermined value is a value corresponding to a desiredlevel of the liquid supply speed.

3060A denotes a step for determining whether the elapsed time t is equalto or less than a second predetermined time, in other words, whether thesecond predetermined time has not yet elapsed since the start of thepuff action has detected. If it is determined that the secondpredetermined time has not yet elapsed, the process proceeds to step3070A, and, if it is not determined so, the process proceeds to step3080A. The second predetermined time corresponds to the above-explainedtime t2 minus the time tStart.

3070A denotes a step for adding a predetermined value ΔA to theparameter A. The predetermined value ΔA corresponds to a value which iscalculated by multiplying a value by a value, wherein the former valueis obtained by dividing a value corresponding to a desired level ofamplitude of the high-frequency voltage by a value obtained bysubtracting the above explained time tStart from the time t2, and thelatter value is a value obtained by subtracting the time when step 3070Awas executed last time from the time at when step 3070A is executed thistime. In the case that the interval between executions of steps 3070A isconstant, AA can be regarded as a constant. Note that, AA may be zerowhen step 3070A is executed for the first time.

3080A denotes a step for determining whether the end of the puff actionis detected. In the case that the end of the puff action is detected,the process proceeds to step 3090A, and, if not, the process returns tostep 3030A.

3090A denotes a step for generating signals for stopping application ofthe high-frequency voltage to the pairs of interlocking comb-shapedmetallic electrodes 33 and stopping supply of the liquid to thepiezoelectric element substrate 31. The above signals may be that whichis to be sent to the atomizing unit 100. Also, the above-explained timetEnd may be a point of time when this step is executed.

FIG. 72 is another example flow chart 3000B for realizing theabove-explained process. The respective steps included in the flow chart3000B may be those executed by the controller 400. Note that, similarlyto the case of the flow chart 3000A, the flow chart 3000B corresponds toa single suction (puff) action, and a similar process may be performedwith respect to each suction action.

3010B, 3020B, 3030B, 3060B, 3070B, 3080B, and 3090B denote steps similarto steps 3010A, 3020A, 3030A, 3060A, 3070A, 3080A, and 3090A included inthe flow chart 3000A.

3040B denotes a step which is similar to step 3040A included in the flowchart 3000A in the point that determination regarding whether the firstpredetermined time has elapsed is performed; however, there is a pointof difference which is that the process proceeds to step 3045B if it isdetermined that the first predetermined time has elapsed, wherein a stepsimilar to step 3045B is not included in the flow chart 3000A.

3045B denotes a step for determining whether the elapsed time t is equalto or less than a third predetermined time, in other words, whether thethird predetermined time has not yet elapsed since the start of the puffaction has detected. If it is determined that the third predeterminedtime has not yet elapsed, the process proceeds to step 3050B, and, if itis not determined so, the process proceeds to step 3060B. The thirdpredetermined time corresponds to the above-explained time t3 minus thetime tStart.

3050B denotes a step for adding a predetermined value Δv to theparameter v. The predetermined value Δv corresponds to a value which iscalculated by multiplying a value by a value, wherein the former valueis obtained by dividing a value corresponding to a desired level of theliquid supply speed by a value obtained by subtracting the aboveexplained time t1 from the time t3, and the latter value is a valueobtained by subtracting the time when step 3050B was executed last timefrom the time when step 3050B is executed this time. In the case thatthe interval between executions of steps 3050B is constant, Δv can beregarded as a constant. Note that, Δv may be zero when step 3050B isexecuted for the first time.

Each of lengths of the first predetermined time, the secondpredetermined time, and the third predetermined time in theabove-explained flow chart may be set, by performing numericalcalculation or performing an experiment, such that generation ofparticles having sizes larger than a predetermined size in atomizationis suppressed.

Note that, although the “droplet having a large diameter,” which isscattered as a bulk droplet and is explained above, includes anextra-large particle having a particle diameter of approximately 100microns which is larger than that of a coarse particle, and a particlehaving a particle diameter larger than that of the extra-large particle,the “droplet” is not limited to that explained above. Accordingly, the“predetermine size” with respect to the above explained “particle largerthan a predetermined size” may be 100 microns, for example.

Note that at least a part of the controller 400 according to themodified example 26D may be realized by a processor. For example, thecontroller 400 may comprise a processor and a memory which stores aprogram, and the program may be that causing the processor to functionas at least a part of the controller 400 according to the modifiedexample 26D.

[Twenty-Sixth Modification E]

In the following, a modified example 26E of the embodiment will beexplained. In the following, differences between embodiments will beexplained mainly.

In the modified example 26E, the quantity of the liquid, which is to beatomized and exists on the piezoelectric element substrate 31, isobtained by use of a sensor, for example, the above-explained sensor1070, for detecting the quantity of the liquid, which is to be atomizedand exists on the piezoelectric element substrate 31; and based on thequantity, supply of the liquid, which is to be atomized, to thepiezoelectric element substrate 31 is controlled; and, by the abovecontrol, scattering by receiving a SAW of a droplet, as a bulk droplethaving a large diameter, from liquid, which is guided to the frontsurface 31F of the piezoelectric element substrate 31, is suppressed.

FIG. 73 is an example flow chart 3100 for realizing a process relatingto the modified example 26E. The respective steps included in the flowchart may be those executed by the controller 400. Note that, similarlyto the case of the flow chart 3000A, the flow chart 3100 corresponds toa single suction (puff) action, and a similar process may be performedwith respect to each suction action.

3110 denotes a step for generating a signal for supplying liquid, whichis to be atomized, to the piezoelectric element substrate 31. The abovesignal may be that which is to be sent to the atomizing unit 100.

3120 denotes a step for determining whether the quantity of the liquid,which is to be atomized and exists on the piezoelectric elementsubstrate 31 (more specifically, on the front surface of thepiezoelectric element substrate 31; this also applies to the following),is in a first predetermined range. In the case that the quantity of theliquid, which is to be atomized, is in the first predetermined range,the process proceeds to step 3130, and, if not, the process returns tostep 3110.

According to the steps 3110 and 3120, the quantity of the liquid, whichis to be atomized and is in the first predetermined range of quantities,would be supplied to the piezoelectric element substrate 31. Note thatthe first predetermined range of quantities may be set, by performingnumerical calculation or performing an experiment, such that generationof particles having sizes larger than a predetermined size issuppressed, when application of the high-frequency voltage to the pairsof interlocking comb-shaped metallic electrodes 33 is started via step3160 which will be explained later.

3130 denotes a step for determining whether the start of a puff actionis detected. In the case that the start of a puff action is detected,the process proceeds to step 3140, and, if not, the process repeats step3130.

3140 denotes a step for initializing an excess flag which will be usedin a later step, that is, a step for making a state in which the flaghas not been set. The excess flag can be realized by use of a memoryincluded in the controller 400.

3141 denotes a step for determining whether an excess flag has been set.In the case that an excess flag has been set, the process proceeds tostep 3142, and, if not, the process proceeds to step 3144.

3142 denotes a step for determining whether the quantity of the liquid,which is to be atomized and exists on the piezoelectric elementsubstrate 31, is less than a lower limit of a second predeterminedrange. In the case that the quantity of the liquid, which is to beatomized, is less than the lower limit of the second predeterminedrange, the process proceeds to step 3143, and, if not, the processproceeds to step 3160.

3143 denotes a step for initializing the excess flag. Step 3143 is astep similar to step 3140.

3144 denotes a step for determining whether the quantity of the liquid,which is to be atomized and exists on the piezoelectric elementsubstrate 31, is equal to or more than an upper limit of the secondpredetermined range. In the case that the quantity of the liquid, whichis to be atomized, is equal to or more than the upper limit of thesecond predetermined range, the process proceeds to step 3145, and, ifnot, the process proceeds to step 3150.

3145 denotes a step for setting the excess flag.

3150 denotes a step for generating a signal for supplying the liquid,with liquid supply speed having magnitude of the parameter v(t), to thepiezoelectric element substrate 31. The above signal may be that whichis to be sent to the atomizing unit 100.

The parameter v(t) may exhibit predetermined change that is a functionof time t elapsed since detection of the start of a puff action in step3130. After at least certain time has elapsed since the start of a puffaction has detected, the value of v(t) or an average value of v(t) overpredetermined time must be larger than speed of consumption of theliquid, which exists on the piezoelectric element substrate 31, byatomization through step 3160 which will be explained later. However,the predetermined change may be a change that is zero for a while sincethe start of a puff action has detected, and, thereafter, become largerthan zero. Also, the parameter v(t) may take a predetermined constantvalue over time.

According to steps 3140-3150, in the case that the quantity of theliquid, which is to be atomized and exists on the piezoelectric elementsubstrate 31, becomes equal to or more than the upper limit of thesecond predetermined range, step 3150 is not executed, and supplying ofthe liquid, which is to be atomized, to the piezoelectric elementsubstrate 31 is stopped. Further, according to steps 3140-3150, aftersupplying of the liquid, which is to be atomized, to the piezoelectricelement substrate 31 is stopped, if the quantity of the liquid, which isto be atomized and exists on the piezoelectric element substrate 31,becomes less than the lower limit of the second predetermined range,step 3150 is executed and supply is restarted. Thus, according to steps3140-3150, the quantity of the liquid, which is to be atomized andexists on the piezoelectric element substrate 31, can be within thesecond predetermined range.

Note that the second predetermined range of quantities may be set, byperforming numerical calculation or performing an experiment, such thatgeneration of particles having sizes larger than a predetermined size,when the high-frequency voltage to the pairs of interlocking comb-shapedmetallic electrodes 33 is applied through step 3160 which will beexplained later. In this regard, the upper limit and the lower limit ofthe second predetermined range of quantities may be equal to or largerthan upper limit and the lower limit of the first predetermined range ofquantities, respectively. Thus, the second predetermined range ofquantities may be equal to the first predetermined range of quantities.

3160 denotes a step for generating a signal for applying, to the pairsof interlocking comb-shaped metallic electrodes 33, a high-frequencyvoltage having amplitude having magnitude corresponding to the parameterA(t) and a frequency corresponding to the parameter f(t). The abovesignal may be that which is to be sent to the atomizing unit 100.

The parameters A(t) and f(t) may exhibit predetermined change that is afunction of time t elapsed since detection of the start of a puff actionin step 3130. Also, the parameters A(t) and/or f(t) may take apredetermined constant value/values over time.

3170 denotes a step for determining whether the end of the puff actionis detected. In the case that the end of the puff action is detected,the process proceeds to step 3180, and, if not, the process returns tostep 3141.

3180 denotes a step for generating signals for stopping application ofthe high-frequency voltage to the pairs of interlocking comb-shapedmetallic electrodes 33 and stopping supply of the liquid to thepiezoelectric element substrate 31. The above signals may be that whichis to be sent to the atomizing unit 100.

Note that, although the “droplet having a large diameter,” which isscattered as bulk a droplet and is explained above, includes anextra-large particle having a particle diameter of approximately 100microns which is larger than that of a coarse particle, and a particlehaving a particle diameter larger than that of the extra-large particle,the “droplet” is not limited to that explained above. Accordingly, the“predetermine size” with respect to the above explained “particle largerthan a predetermined size” may be 100 microns, for example.

Note that at least a part of the controller 400 according to themodified example 26E may be realized by a processor. For example, thecontroller 400 may comprise a processor and a memory which stores aprogram, and the program may be that causing the processor to functionas at least a part of the controller 400 according to the modifiedexample 26E.

[Twenty Seventh Modification]

The inhaler 1 of the present invention may be configured to apply aconsistently appropriate frequency to a pair of interlocking comb-shapedelectrodes 33 of an interdigital transducer (IDT).

FIG. 74 is a flow chart illustrating a method of operating the inhaler 1according to the present modification. Hereafter, the method will beexplained on the assumption that all the steps illustrated in FIG. 74are carried out by the controller 400 of the inhaler 1. It should benoted, however, that at least some of the steps may be carried out byone or more of the other components of the inhaler 1. Further, it shouldbe apparent that when the present modification is carried out by aprocessor such as the controller 400 or the like, the presentmodification can be implemented as a program for causing the processorto carry out a method or as a computer readable storage medium in whichthe program is stored. The same could be said of the flow charts shownin FIGS. 76, 79, 80A, 80B, 80C, 81A, 81B, 81C, 82 and 83.

At step 4002, the controller 400 determines whether a request to atomizeliquid to be stored in the liquid storage unit 200 is detected. Theinhaler 1 may comprise a power source switch and a drive switch forliquid atomization. The power source switch and the drive switch may beseparate switches. Alternatively, one switch may have the functions ofboth a power source switch and a drive switch. Further, when the powersource switch and the drive switch are separate switches, the powersource switch may be a dip switch. The power source switch may bedesigned such that when the power source switch is turned on, apredetermined amount of liquid is supplied to be inhalable. The driveswitch may be in the form of a button, so that when a user depresses thedrive switch, power is supplied. In one example, the controller 400 maybe configured to determine that a request to atomize liquid is detectedwhen the drive switch is depressed. In another example, the controller400 may be configured to determine that a request to atomize liquid isdetected when inhalation by a user is detected. For example, the inhaler1 may comprise a pressure sensor and the controller 400 may beconfigured to detect inhalation by a user based on the variation inpressure detected by the pressure sensor, etc.

When a request to atomize liquid is not detected (“N” at step 4002), theprocess returns to the step preceding step 4002. In contrast, when arequest to atomize liquid is detected (“Y” at step 4002), the processproceeds to step 4004.

At step 4004, the controller 400 monitors a resonant frequency of thepair of interlocking comb-shaped electrodes 33. A specific configurationfor carrying out step 4004 will be described below.

FIG. 75 illustrates an example of the control circuit 4100 of theinhaler 1. The control circuit 4100 is configured to control thefrequency of the voltage applied to the pair of interlocking comb-shapedelectrodes 33 and monitor a resonant frequency of the pair ofinterlocking comb-shaped electrodes 33. In this example, the controlcircuit 4100 comprises a MEMS oscillator 4102, DC/DC converter 4103,power amplifier 4104, two-way coupler 4106, power detector 4108A andpower detector 4108B in addition to the controller 400. The controller400 communicates with the MEMS oscillator 4102 to thereby control anoscillatory frequency of the MEMS oscillator 4102. The MEMS oscillator4102 outputs an indicated oscillatory frequency. The DC/DC converter4103 supplies to the power amplifier 4104 a voltage indicated by thecontroller 400. The power amplifier 4101 is connected to the powersource 500 and amplifies a voltage supplied from the power source 500with a voltage supplied from the DC/DC converter. The power amplifier4101 may be configured to modulate the voltage with an oscillatoryfrequency received from the MEMS oscillator 4102. The controller 400 canamplitude-modulate a voltage output from the power amplifier 4101 bychanging a supply voltage from the DC/DC converter 4103. In one example,a modulation frequency for the amplitude-modulation may be 100 Hz.

The two-way coupler 4106 receives an output from the power amplifier4104, supplies a portion of the received output to the pair ofinterlocking comb-shaped electrodes 33 of the IDT and outputs anotherportion of the received output to the power detector 4108A. In otherwords, the power detector 4108A detects power (or voltage) supplied tothe pair of interlocking comb-shaped electrodes 33 in the forwarddirection. The analog-digital conversion is performed on a power valuedetected by the power detector 4108A and the converted value is suppliedto the controller 400. The two-way coupler 4106 receives power (orvoltage) reflected from the pair of interlocking comb-shaped electrodes33 and supplies at least a portion of the received power to the powerdetector 4108B. In other words, the power detector 4108B detects reversepower reflected from the pair of interlocking comb-shaped electrodes 33.The analog-digital conversion is performed on a power value detected bythe power detector 4108B and the converted value is supplied to thecontroller 400.

FIG. 76 is a flow chart illustrating a specific example of a processperformed at step 4004 in FIG. 74. At step 4202, the controller 400applies a voltage to the pair of interlocking comb-shaped electrodes 33at a frequency selected from multiple different frequencies. Next, atstep 4204, the controller 400 determines as a resonant frequency, thefrequency of the voltage applied to the pair of interlocking comb-shapedelectrodes 33 when power reflected from the pair of interlockingcomb-shaped electrodes 33 is the lowest.

FIG. 77 illustrates a specific example of a method of determining aresonant frequency in the process illustrated in FIG. 76. FIG. 77(a)will be described below. The controller 400 determines multipledifferent frequencies (f1-f9) used to determine a resonant frequency.The controller 400 first selects a frequency f1 from the multipledifferent frequencies and controls the MEMS oscillator 4102 so as tooutput a signal of the oscillatory frequency f1. Based on a signalreceived from the MEMS oscillator 4102, the power amplifier 4104 outputsa voltage that fluctuates at frequency f1. The thus output voltage isapplied to the pair of interlocking comb-shaped electrodes 33 of IDT viathe two-way coupler 4106. If the frequency f1 and the resonant frequencyof the pair of interlocking comb-shaped electrodes 33 do not completelymatch, a portion of power supplied to the pair of interlockingcomb-shaped electrodes 33 is reflected to be input to the power detector4108B via the two-way coupler 4106. Thus, the controller 400 obtains avalue of reflected power. FIG. 77(a) is a plot showing the relationshipbetween reflected power and frequencies f1-f9. When the frequency is f6,power reflected from the pair of interlocking comb-shaped electrodes 33is the lowest. Thus, the controller 400 determines f6 as a resonantfrequency.

Parameters to be set in advance with respect to the method described inFIG. 77 can be the number of points (frequencies) to be scanned, afrequency range to be scanned, an interval between adjacent frequencies,etc. In FIG. 77(a), frequencies are scanned at nine points f1-f9. Sincethe intervals between the respective adjacent frequencies are relativelylarge, there can be some gap between the resonant frequency f6 detectedby scanning and the true resonant frequency. On the other hand, if thereare more frequencies to be scanned in the same frequency range, theintervals between the respective adjacent frequencies naturally becomesmaller, which enables more accurate determination of a resonantfrequency. As described above, the controller 400 is able to flexiblyprovide for a variety of accuracies demanded for resonant frequencydetection, by changing configurable parameters.

In one example, the controller 400 may be configured to detect firstpower reflected from the pair of interlocking comb-shaped electrodes 33when a voltage is applied to the pair of interlocking comb-shapedelectrodes 33 at a first frequency (for example, f1). The controller 400may be configured to detect second power reflected from the pair ofcomb-shaped electrodes 33 when a voltage is subsequently applied to thepair of interlocking comb-shaped electrodes 33 at a second frequency(for example, f2) separated from the first frequency by a first value.When the second power is lower than the first power, the controller 400may next apply a voltage to the pair of interlocking comb-shapedelectrodes 33 at a third frequency (for example, f3) separated from thesecond frequency by a second value that is smaller than the first value,in which case a frequency interval between f2 and f3 may be set to besmaller than the frequency interval between f1 and f2. According to thisexample, when a frequency of a voltage applied to the pair ofinterlocking comb-shaped electrodes 33 is greatly separated from aresonant frequency, a frequency scanning operation is conducted withwide intervals between the respective adjacent frequencies, whereas asthe frequency of the voltage to be applied approaches a resonantfrequency, a frequency scanning operation is conducted with narrowintervals between the respective adjacent frequencies. Thus, a lessdetailed scan is carried out where the frequency intervals are large anda detailed scan does not have to be carried out over the entirefrequency range, which advantageously reduces time required formonitoring a resonant frequency.

In one example, the controller 400 may be configured to monitorreflected power from the pair of interlocking comb-shaped electrodes 33while discretely increasing or decreasing the frequency of the voltageapplied to the pair of interlocking comb-shaped electrodes 33. Thecontroller 400 may be configured to end a scan when the trend of thevalue indicating reflected power shifts from a decreasing trend to anincreasing trend and determine as a resonant frequency, the frequency ofthe voltage applied to the pair of interlocking comb-shaped electrodes33 when reflected power becomes the lowest. According to this example,the range of frequencies to be scanned can be decreased, whichadvantageously reduces time required for monitoring a resonantfrequency.

In one example, the controller 400 may be configured to monitorreflected power from the pair of interlocking comb-shaped electrodes 33while discretely increasing the frequency of the voltage applied to thepair of interlocking comb-shaped electrodes 33. The controller 400 maybe configured to reduce the range of variation in the frequency of thevoltage applied to the pair of interlocking comb-shaped electrodes 33and discretely decrease the frequency when the trend of the valueindicating reflected power shifts from a decreasing trend to anincreasing trend. According to this example, a less detailed scan iscarried out where the frequency intervals are large and a detailed scandoes not have to be carried out over the entire frequency range, whichadvantageously reduces time required for monitoring a resonantfrequency.

In one example, the controller 400 may be configured to monitorreflected power from the pair of interlocking comb-shaped electrodes 33while discretely decreasing the frequency of the voltage applied to thepair of interlocking comb-shaped electrodes 33. The controller 400 maybe configured to reduce the range of variation in the frequency of thevoltage applied to the pair of interlocking comb-shaped electrodes 33and discretely increase the frequency when the trend of the valueindicating reflected power shifts from a decreasing trend to anincreasing trend. According to this example, a less detailed scan iscarried out where the frequency intervals are large and a detailed scandoes not have to be carried out over the entire frequency range, whichadvantageously reduces time required for monitoring a resonantfrequency.

In one example, the controller 400 may be configured to determine aresonant frequency monitored before the start of atomization of liquidby the atomizing unit 100, a resonant frequency estimated from thetemperature of the piezoelectric element substrate 31 or a frequencyclosest to the resonant frequency at the time of the previous inhalationas a frequency to be selected first from the multiple differentfrequencies.

FIG. 78A illustrates an example of a configuration of the inhaler 1according to the present modification for determining a resonantfrequency by a method different from the method explained with referenceto FIG. 77. In addition to the IDT (hereafter referred to as a firstIDT) comprising the main body portion 32 and pair of interlockingcomb-shaped electrodes 33, a second IDT comprising the main body portion4432 and pair of interlocking comb-shaped electrodes 4433 is disposed onthe piezoelectric element substrate 31. The second IDT may have asimilar configuration to the first IDT. The second IDT is provided at aposition where a SAW (surface acoustic wave) output from the first IDTpasses. As is illustrated in FIG. 78A, the second IDT is disposed suchthat the intersection of the second IDT and the intersection of thefirst IDT at least partially overlap one another along the direction ofpropagation of a SAW. The second IDT may be smaller than the first IDTor as large as the first IDT. When the second IDT is smaller than thefirst IDT, the second IDT may be disposed only on one side of the firstIDT as illustrated in FIG. 78A or at least one second IDT may bedisposed on each side of the first IDT. Since a SAW is partiallyconverted to a voltage or heat by the second IDT, a SAW decreases as itis output from the first IDT and passes through the second IDT. Thus,when the second IDT is as large as the first IDT, it should be disposedonly on one side of the first IDT for the sake of efficiency.

If the second IDT is provided at a position where a SAW (surfaceacoustic wave) passes as is described in the foregoing example, such aconfiguration presents a problem that the electrodes of the second IDTcould come off due to surface acoustic wave vibration. With a view tosolving the problem, the first IDT and the second IDT in the presentmodification may be first disposed on the piezoelectric elementsubstrate 31 and then, a coating layer may be provided on thepiezoelectric element substrate 31, which could preventvibration-induced detachment of the electrodes of the IDT.

FIG. 78B illustrates an example of the placement of the first and secondIDTs. The first IDT (supply IDT) for supplying AC voltage and the secondIDT (detection IDT) for detecting the frequency of the supplied voltageare disposed on the piezoelectric element substrate 31. The AC voltagesupply circuit 4442 is connected to the first IDT. The voltage detectioncircuit 4444 is connected to the second IDT. When a voltage is suppliedby the AC voltage supply circuit 4442 to the first IDT, a SAW isgenerated on either side of the first IDT. As was explained inconnection with FIG. 78A, the second IDT could assume various sizes. Inthe example illustrated in FIG. 78B, the second IDT and the first IDTare the same size. In FIG. 78B, a SAW on one side of the first IDT thatpropagates rightward from the first IDT, is used to atomize liquid,whereas a SAW on the other side of the first IDT that propagatesleftward from the first IDT, is used by the second IDT to detect avoltage.

FIG. 78C illustrates an example of the arrangement of the first andsecond IDTs. In the example illustrated in FIG. 78C, the second IDT issmaller than the first IDT. The second IDT uses a portion of a SAW thatpropagates leftward from the first IDT to pick up power (voltage.) Inthis example, a SAW generated on either side of the first IDT can beused to atomize liquid.

FIG. 78D illustrates an example of the arrangement of the first andsecond IDTs. In this example, the first and second IDTs are disposed tohave a common reference voltage. Since the number of a pair ofinterlocking comb-shaped electrodes of the second IDT is smaller thanthe number of pair of interlocking comb-shaped electrodes of the firstIDT in this example, SAW reduction is prevented and power (voltage) canbe picked up.

A device that generates a SAW such as the first IDT illustrated in FIGS.78A-78D tends to generate heat when high power is supplied to thedevice. Since such a device as described above usually has a narrowrange of frequencies at which impedance matching is achieved, afrequency, at which impedance matching is achieved, sometimes changeswith temperature variations. Considering that low power consumption isrequired when such a device is used in portable equipment, it isdesirable to be able to detect a matching frequency with low powerconsumption. Therefore, when monitoring a resonant frequency of the pairof interlocking comb-shaped electrodes 33 of the first IDT, electricpower lower than necessary for atomizing liquid may be supplied to thefirst IDT, and after determining the frequency of the voltage to beapplied to the pair of interlocking comb-shaped electrodes 33, higherelectric power necessary for atomization may be supplied to the firstIDT. Thereby, power consumption in monitoring a resonant frequency canbe reduced.

FIG. 79 is a flow chart illustrating a specific example of a processperformed at step 4004 in FIG. 74. The process illustrated in FIG. 79can be implemented by applying the configurations shown in FIGS. 78A to78D to the inhaler 1. At step 4502, the controller 400 applies a voltageto the pair of interlocking comb-shaped electrodes 33 at a frequencyselected from multiple different frequencies (for example, f1-f9.) Next,at step 4504 the controller 400 determines as a resonant frequency, thefrequency of the voltage applied to the pair of interlocking comb-shapedelectrodes 33 when a voltage generated at the second IDT is the highest.

In one example, the controller 400 may detect a first voltage arising atthe second IDT when a voltage is applied to the interlocking comb-shapedelectrodes 33 at a first frequency (for example, f1). Next, thecontroller 400 may detect a second voltage arising at the second IDTwhen a voltage is applied to the interlocking comb-shaped electrodes 33at a second frequency (for example, f2) separated from the firstfrequency by a first value. When the second voltage is higher than thefirst voltage, the controller 400 may apply a voltage to the pair ofinterlocking comb-shaped electrodes 33 at a third frequency (forexample, f3) separated from the second frequency by a second value thatis smaller than the first value.

In one example, the controller 400 may monitor a voltage that arises atthe second IDT while discretely increasing or decreasing the frequencyof the voltage applied to the pair of interlocking comb-shapedelectrodes 33. The controller 400 may be configured to end a scan whenthe trend of the value of a voltage arising at the second IDT shiftsfrom an increasing trend to a decreasing trend and determine as aresonant frequency, the frequency of the voltage applied to the pair ofinterlocking comb-shaped electrodes 33 when the voltage becomes thehighest.

In one example, the controller 400 may be configured to monitor avoltage arising at the second IDT while discretely increasing thefrequency of the voltage applied to the pair of interlocking comb-shapedelectrodes 33. The controller 400 may be configured to reduce the rangeof variation in the frequency of the voltage applied to the pair ofinterlocking comb-shaped electrodes 33 and discretely decrease thefrequency when the trend of the value of a voltage arising at the secondIDT shifts from an increasing trend to a decreasing trend.

In one example, the controller 400 may be configured to monitor avoltage arising at the second IDT while discretely decreasing thefrequency of the voltage applied to the pair of interlocking comb-shapedelectrodes 33. The controller 400 may be configured to reduce the rangeof variation in the frequency of the voltage applied to the pair ofinterlocking comb-shaped electrodes 33 when the trend of the value of avoltage arising at the second IDT shifts from an increasing trend to adecreasing trend.

In one example, the controller 400 may be configured to determine aresonant frequency monitored before the start of atomization of liquidby the atomizing unit 100, a resonant frequency estimated from thetemperature of the piezoelectric element substrate 31 or a frequencyclosest to the resonant frequency at the time of the previous inhalationas a frequency to be selected first from multiple different frequencies.

Returning to FIG. 74, at step 4004 a resonant frequency of the pair ofinterlocking comb-shaped electrodes 33 is monitored and a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes 33 isdetermined based on the monitored resonant frequency by use of theconfiguration and process described in FIGS. 75 to 79. Next, at step4006 the controller 400 applies a voltage to the pair of interlockingcomb-shaped electrodes 33 at the determined frequency.

Manufacturing variations in terms of inter-electrode distance and thelike can occur in an IDT for an inhaler. Further, a resonant frequencyof a pair of interlocking comb-shaped electrodes of an IDT variesdepending on the usage temperature of an inhaler, etc. Accordingly, aconventional inhaler cannot attain a sufficient amount of atomizedliquid under various circumstances. According to the presentmodification, a resonant frequency of a pair of interlocking comb-shapedelectrodes can be monitored and a frequency of a voltage to be appliedto the pair of interlocking comb-shaped electrodes can be dynamicallycontrolled. Thus, an inhaler according to the present modification canapply a voltage at a frequency appropriate for a pair of interlockingcomb-shaped electrodes and provide a sufficient amount of atomizedliquid under various circumstances even if a resonant frequency of thepair of interlocking comb-shaped electrodes varies due to manufacturingvariations, usage temperature, etc.

FIG. 80A is a flow chart illustrating a method of operating the inhaler1 according to the present modification. At step 4604A the controller400 performs a control operation so that the inhaler 1 enters a standbymode (state where liquid is supplied to the proper level foratomization, so that upon application of a voltage, liquid can beatomized at any moment.) The controller 400 may be configured to monitorthe liquid surface level to determine whether liquid is supplied to theproper level for atomization. The controller 400 may be configured tomonitor the liquid surface level while monitoring a resonant frequencyof the pair of interlocking comb-shaped electrodes 33. Alternatively,the controller 400 may be configured to monitor a resonant frequency ofthe pair of interlocking comb-shaped electrodes 33 after it isdetermined that liquid is supplied to the proper level for atomization.

The process proceeds to step 4607A, where the controller 400 determineswhether a request to atomize liquid is detected (whether the driveswitch of the inhaler 1 is depressed, whether inhalation by a user isdetected, etc.) If it transpires that a request to atomize liquid is notdetected (“N” at step 4607A), the process returns to the processpreceding step 4607A.

If it transpires that a request to atomize liquid is detected (“Y” atstep 4607A), the process proceeds to step 4608A and the controller 400starts atomization of liquid by the atomizing unit 100. In other words,the controller 400 is configured to monitor a resonant frequency (step4604A) before the start of the atomization of liquid by the atomizingunit 100 (step 4608A).

The process proceeds to step 4610A and the controller 400 applies avoltage to the pair of interlocking comb-shaped electrodes 33 at afrequency determined based on the resonant frequency monitored at step4604A, while the atomizing unit 100 atomizes liquid.

FIG. 80B is a flow chart illustrating a method of operating the inhaler1 according to the present modification. Since the process at steps4601B, 4602B and 4604B is similar to the process at steps 4604A, 4607Aand 4608A, an explanation for steps 4601B, 4602B and 4604B is omittedhere.

At step 4606B the controller 400 applies a voltage to the pair ofinterlocking comb-shaped electrodes 33 at the resonant frequencymonitored in the standby mode at the time of the first inhalation and ata frequency based on the resonant frequency determined for theimmediately previous inhalation at the time of inhalation from thesecond time onward.

At step 4608B the controller 400 monitors a resonant frequency of thepair of interlocking comb-shaped electrodes 33 upon completion ofatomization of liquid by the atomizing unit 100. The monitored resonantfrequency may be stored in the memory unit. At the time of the nextinhalation, the resonant frequency is used to determine a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes 33during atomization of liquid.

In other words, the controller 400 is configured to monitor a resonantfrequency after completion of atomization of liquid by the atomizingunit 100, in the process 4600B shown in FIG. 80B.

FIG. 80C is a flow chart illustrating a method of operating the inhaler1 according to the present modification. Since the process at step 4604Cis similar to the process at step 4604A, an explanation for step 4604Cis omitted here.

At step 4606C the controller 400 determines a frequency range includingthe monitored resonant frequency. In one example, when a monitoredresonant frequency is 25 MHz, the controller 400 may determine 24.9 MHzto 25.1 MHz as a frequency range. In this example, a frequency range maybe determined such that a resonant frequency of the pair of interlockingcomb-shaped electrodes 33 falls within the frequency range even if thetemperature of the piezoelectric element substrate 31 changes as aresult of usage of the inhaler 1. The inhaler 1 may comprise a memoryunit for storing a correspondence between a resonant frequency and afrequency range applied to the resonant frequency. The controller 400may be configured to determine a frequency range based on a monitoredresonant frequency and a correspondence stored in the memory unit.

The process proceeds to step 4607C, where the controller 400 determineswhether a request to atomize liquid is detected (whether the driveswitch of the inhaler 1 is depressed, whether inhalation by a user isdetected, etc.) If it transpires that a request to atomize liquid is notdetected (“N” at step 4607C), the process returns to the step precedingstep 4607C.

If it transpires that a request to atomize liquid is detected (“Y” atstep 4607C), the process proceeds to step 4608C and the controller 400starts atomization of liquid by the atomizing unit 100. In other words,the controller 400 is configured to monitor a resonant frequency (step4604C) before the start of the atomization of liquid by the atomizingunit 100 (step 4608C), in the process 4600C shown in FIG. 80C.

The process proceeds to step 4610C and the controller 400 controls afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes 33 (for example, by controlling an oscillatory frequency ofthe MEMS oscillator 4102) during atomization of liquid by the atomizingunit 100 so as to fall within the frequency range determined at step4606C. The controller 400 may be configured to control a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes 33during atomization of liquid by the atomizing unit 100 so as to varywithin the frequency range. For example, the controller 400 may beconfigured to control a frequency of a voltage to be applied so as toperiodically vary within the frequency range. If a frequency of avoltage applied to the pair of interlocking comb-shaped electrodes 33 isallowed to vary within a predetermined frequency range (for example,24.9 MHz to 25.1 MHz) during atomization of liquid, electric power canbe supplied at a resonant frequency for a certain period of time withouthaving to monitor a resonant frequency each time inhalation occurs.

According to the present modification, a resonant frequency of a pair ofinterlocking comb-shaped electrodes is monitored to dynamically controla frequency of a voltage to be applied to the pair of interlockingcomb-shaped electrodes. Thus, an inhaler according to the presentmodification can apply a voltage at a frequency appropriate for a pairof interlocking comb-shaped electrodes and provide a sufficient amountof atomized liquid under various circumstances even if a resonantfrequency of the pair of interlocking comb-shaped electrodes differsfrom a design value due to manufacturing variations, etc.

According to the present modification, a resonant frequency isdetermined only once before the start of atomization of liquid, whichsimplifies a process performed by a controller. A controller monitors aresonant frequency at the time of performing a process for entering astandby mode, determines a frequency for atomization based on the thusobtained resonant frequency before atomization and applies thedetermined frequency for atomization. In other words, the controller 400does not monitor a resonant frequency each time inhalation occurs, whichenables the controller 400 to use the time in which a user is inhalingto atomize liquid. Thus, the present modification can secure asufficient amount of atomized liquid, compared to a case when a resonantfrequency is monitored every time a user inhales.

FIG. 81A is a flow chart illustrating a method of operating the inhaler1 according to the present modification. Since the process at step 4704Ais similar to the process at step 4604A, an explanation for step 4704 isomitted here.

At step 4706A the controller 400 determines based on the valuesmonitored at step 4704A, an initial value of a resonant frequency forthe pair of interlocking comb-shaped electrodes 33 used at the time ofthe first inhalation.

The process proceeds to step 4707A, where the controller 400 determineswhether a request to atomize liquid is detected (whether the driveswitch of the inhaler 1 is depressed, whether inhalation by a user isdetected, etc.) If it transpires that a request to atomize liquid is notdetected (“N” at step 4707A), the process returns to the step precedingstep 4707A.

In contrast, if it transpires that a request to atomize liquid isdetected (“Y” at step 4707A), the process proceeds to step 4708A and thecontroller 400 sets an initial value of a frequency of a voltage appliedto the pair of interlocking comb-shaped electrodes 33. At the time ofthe first inhalation, the initial value is a value determined at step4706A. At the time of inhalation from the second time onward, theinitial value set at step 4708A may be a resonant frequency monitored atthe time of the previous inhalation. At step 4709A the controller 400starts atomization of liquid by the atomizing unit 100. Next, at step4710A the controller 400 applies a voltage to the pair of interlockingcomb-shaped electrodes 33 at a frequency (fixed value) determined basedon the initial value.

At step 4712A the controller 400 monitors a resonant frequency of thepair of interlocking comb-shaped electrodes 33, during atomization ofliquid by the atomizing unit 100.

At step 4714A the controller 400 applies a voltage to the pair ofinterlocking comb-shaped electrodes 33 at a frequency determined basedon the monitored resonant frequency, which enables fine adjustments inthe frequency for the current or next inhalation. From that timeonwards, the process at step 4710A to step 4714A may be repeated duringatomization of liquid.

FIG. 81B is a flow chart illustrating a method of operating the inhaleraccording to the present modification. Since the process at step 4704Bto step 4709B is similar to the process at step 4704A to step 4709A, anexplanation for the process at step 4704B to step 4709B is omitted here.

At step 4710B the controller 400 is configured to control a voltageapplied to the pair of interlocking comb-shaped electrodes 33 so as tovary within a predetermined range of frequencies including a frequencydetermined based on the initial value. For example, the controller 400may be configured to vary a frequency of a voltage applied to the pairof interlocking comb-shaped electrodes 33 within a narrow range offrequencies including the initial value (for example, initial value+/−0.1 MHz).

At step 4712B, the controller 400 monitors a resonant frequency of thepair of interlocking comb-shaped electrodes 33, during atomization ofliquid by the atomizing unit 100. In the example shown in FIG. 81B, avoltage applied to the pair of interlocking comb-shaped electrodes 33 iscontrolled so as to vary within a predetermined range of frequencies, atstep 4710B. Thus, a resonant frequency can be monitored at the same timeas liquid is atomized. On the other hand, in the example shown in FIG.81A, atomization of liquid must be stopped during the process ofmonitoring a resonant frequency. Thus, compared to the exampleillustrated in FIG. 81A, the example shown in FIG. 81B comprises theforegoing additional feature.

At step 4714B the controller 400 adjusts a predetermined range offrequencies used at step 4710B so as to include the resonant frequencymonitored at step 4712B, which enables fine adjustments in the frequencyfor the current inhalation. From that time onwards, the process at step4710B to step 4714B may be repeated during atomization of liquid.

FIG. 81C is a flow chart illustrating a method of operating the inhaler1 according to the present modification. Since the process at step 4704Cto step 4712C is similar to the process at step 4704B to step 4712B, anexplanation for the process at step 4704C to step 4712C is omitted here.

At step 4714C the controller 400 determines the resonant frequencymonitored at the step 4712C as a frequency of a voltage applied to thepair of interlocking comb-shaped electrodes 33 at the time of the nextinhalation. The thus determined frequency may be stored in a memoryunit. When the inhalation action occurs next time, the controller 400applies a voltage to the pair of interlocking comb-shaped electrodes 33at a frequency determined at step 4714C.

According to the present modification, a frequency of a voltage appliedto a pair of interlocking comb-shaped electrodes can be appropriatelyset while a user is using an inhaler and liquid is atomized. Thus, thepresent modification can provide detailed control suited for thecondition of an inhaler, which changes from moment to moment, thereby tooptimize the liquid atomization amount.

FIG. 82 is a flow chart illustrating a method of operating the inhaler 1according to the present modification. Since the process at step 4804 tostep 4810 is similar to the process at step 4704A to step 4710A, anexplanation for the process at step 4804 to step 4810 is omitted here.

The inhaler 1 may comprise a temperature sensor configured to detect thetemperature of the piezoelectric element substrate 31 that contributesto the phase and amplification of a SAW. The temperature sensor may beconfigured to detect the temperature of the appropriate component of theinhaler 1 other than the piezoelectric element substrate 31. Thetemperature sensor may be provided at any appropriate position in theinhaler 1. Alternatively, the temperature may be measured by havingthermocouples, thermistors or the like contact the components, in whichcase the temperature of the substrate surface in the neighborhood of thepair of interlocking comb-shaped electrodes 33 may be measured toprevent short circuits. Alternatively, a non-contact temperaturemeasuring system such as a radiation thermometer using infrared may beemployed, in which case the temperature of the pair of interlockingcomb-shaped electrodes 33 may be measured.

At step 4812 the controller 400 obtains the temperature detected by thetemperature sensor, during atomization of liquid by the atomizing unit100. The process proceeds to step 4814, where the controller 400determines a frequency of a voltage applied to the pair of interlockingcomb-shaped electrodes 33 based on the temperature detected at step4812.

FIG. 83 is a flow chart illustrating a specific example of a processperformed at step 4814. At step 4902 the controller 400 predicts aresonant frequency variation during atomization of liquid by theatomizing unit 100, based on the temperature detected at step 4812.Since the velocity of propagation of a SAW increases as the temperaturerises, the resonant frequency tends to increase. Thus, the controller400 may predict a resonant frequency variation by utilizing suchtendency. Alternatively, the inhaler 1 may comprise a memory unit andthe memory unit may store information regarding correspondence betweenthe temperature of the piezoelectric element substrate 31 (or otherappropriate component) and the resonant frequency. The controller 400may be configured to predict a variation in the resonant frequency ofthe pair of interlocking comb-shaped electrode 33 (or other appropriatecomponent) based on the measured temperature of the piezoelectricelement substrate 31 (or other appropriate component) and the foregoinginformation.

The process proceeds to step 4904 and the controller 400 determines afrequency of a voltage applied to the pair of interlocking comb-shapedelectrodes 33 based on resonant frequency variation predicted at step4902.

Referring back to FIG. 82, at step 4816 the controller 400 applies avoltage to the pair of interlocking comb-shaped electrodes 33 at afrequency determined at step 4814.

According to the present modification, a resonant frequency of a pair ofinterlocking comb-shaped electrodes can be monitored to dynamicallycontrol a frequency of a voltage that is applied to the pair ofinterlocking comb-shaped electrodes. Further, a variation in a resonantfrequency of the pair of interlocking comb-shaped electrodes duringatomization of liquid can be predicted by also using the temperaturedetected by a temperature sensor. Thus, the present modification canapply a voltage at a frequency appropriate for a pair of interlockingcomb-shaped electrodes and provide a sufficient amount of atomizedliquid under various circumstances even if a resonant frequency of thepair of interlocking comb-shaped electrodes varies due to manufacturingvariations, usage temperature, etc. Further, the present modificationcan provide detailed control suited for the condition of an inhaler,which changes from moment to moment, thereby to optimize the liquidatomization amount.

In another example, the controller 400 may be configured to detect thetemperature before the start of atomization of liquid by the atomizingunit 100 and determine a frequency of a voltage applied to the pair ofinterlocking comb-shaped electrodes 33 based on the thus detectedtemperature. According to the foregoing configuration, the temperatureis detected only once before the start of atomization of liquid, whichenables precise control of a resonant frequency by a relatively simpleprocess.

Other Embodiments

The present invention has been described in terms of the embodiment setforth above; however, the invention should not be understood to belimited by the statements and the drawings constituting a part of thisdisclosure. From this disclosure, various alternative embodiments,examples, and operational technologies will become apparent to thoseskilled in the art.

In the embodiment, the liquid supplier 60 is provided on the side of therear surface 31B of the piezoelectric element substrate 31. However, theembodiment is not limited thereto. For example, the liquid supplier 60may be provided on the side of the front surface 31F of thepiezoelectric element substrate 31. In such a case, the liquid supplier60 may drop the liquid onto the front surface 31F of the piezoelectricelement substrate 31. Further, the piezoelectric element substrate 31may not need to have the penetrated aperture 34.

In the embodiment, the pairs of interlocking comb-shaped metallicelectrodes 33 have a linear shape. However, the embodiment is notlimited thereto. For example, the pairs of interlocking comb-shapedmetallic electrodes 33 may have a fan shape.

In the embodiment, the number of pairs of interlocking comb-shapedmetallic electrodes 33 is determined based on the atomizing efficiencyof the aerosol atomized by use of the SAW. However, the embodiment isnot limited thereto. For example, the number of pairs of interlockingcomb-shaped metallic electrodes 33 may be determined based on amagnitude of power that can be supplied to the pairs of interlockingcomb-shaped metallic electrodes 33. The number of pairs of interlockingcomb-shaped metallic electrodes 33 may be determined based on the typeof solute or solvent configuring the liquid. the number of pairs ofinterlocking comb-shaped metallic electrodes 33 may be determined basedon a supplying method and a supplying speed of the liquid supplied tothe SAW module.

In the embodiment, the flavor inhaler 1 has the inlet 1A. However, theembodiment is not limited thereto. The flavor inhaler 1 may not need tohave the inlet 1A. In such a case, a user inhales the aerosol flowingout from the mouthpiece 1D together with outside air without holding themouthpiece 1D with a mouth.

Although not particularly mentioned in the embodiment, the amount ofaerosol inhaled by a user may be settable by the user. The flavorinhaler 1 may adjust, based on the amount of aerosol set by the user,the voltage applied to the SAW module 30, and may adjust the amount ofliquid supplied to the SAW module 30 from the liquid supplier 60.

In the embodiment, a case has been exemplified in which the flavorinhaler 1 has one SAW module 30. However, the embodiment is not limitedthereto. The flavor inhaler 1 may have two or more SAW modules 30.

Although not particularly mentioned in the embodiment, the flavorinhaler 1 may have a power source switch. The flavor inhaler 1 mayoperate in a drive mode in response to turning on the power source. Thedrive mode is a mode in which the power is supplied to eachconfiguration provided in the flavor inhaler 1, and for example, is amode in which the atomization action of the atomizing unit 100 can bestarted. The flavor inhaler 1 may operate in a standby mode in a statewhere the power source switch is turned off. The standby mode is a modeoperating at standby power that can detect whether the power sourceswitch is turned on.

Although not particularly mentioned in the embodiment, the flavorinhaler 1 may have a temperature sensor configured to detect atemperature (for example, atmospheric temperature) of the flavor inhaler1. If the temperature of the flavor inhaler 1 falls below a lower limittemperature, the flavor inhaler 1 may have a function of not performingthe atomization action of the liquid. If the temperature of the flavorinhaler 1 exceeds a higher limit temperature, the flavor inhaler 1 mayhave a function of not performing the atomization action of the liquid.

Although not particularly mentioned in the embodiment, the flavorinhaler 1 may have a remaining amount sensor configured to detect theremaining amount of the liquid. The remaining amount sensor may beprovided within the penetrated aperture 34 and may detect a liquidsurface level of the liquid within the penetrated aperture 34. Thesurface water level of the liquid may be controlled by a detectionresult of the remaining amount sensor. If at least any one of theatomizing unit 100 and the liquid storage unit 200 is a cartridge, theflavor inhaler 1 may have a detecting sensor configured to detect apresence or an absence of the cartridge. If there is no cartridge, theflavor inhaler 1 may have a function of not performing the atomizationaction of the liquid.

In the embodiment, the flavor inhaler 1 has the sensor 300. However, theembodiment is not limited thereto. The flavor inhaler 1 may have,instead of the sensor 300, a drive switch used to drive the atomizingunit 100. The flavor inhaler 1 may start the atomization action of theatomizing unit 100 in response to the drive switch being turned on. Theflavor inhaler 1 may stop the atomization action of the atomizing unit100 in response to the drive switch being turned off. If a certainperiod has passed from a switch-on of the drive switch, the flavorinhaler 1 may stop the atomization action of the atomizing unit 100.

Although not particularly mentioned in the embodiment, a switch providedon the flavor inhaler 1 may be a switch other than the above-describedpower source switch and drive switch. For example, the switch may be theone configured to switch two or more operation modes of the flavorinhaler 1. The switch provided on the flavor inhaler 1 may be amechanical switch or a touch panel.

Although not particularly mentioned in the embodiment, the flavorinhaler 1 may have a function of returning, to the liquid storage unit200, an unused liquid within a pipe for supplying the liquid from theliquid storage unit 200 to the atomizing unit 100. The flavor inhaler 1may have a structure of preventing the unused liquid from flowing outthrough the mouthpiece 1D, such as a liquid reservoir structureconfigured to reserve and recycle the unused liquid.

INDUSTRIAL APPLICABILITY

According to the embodiment, it is possible to provide an atomizing unitby which atomizing efficiency of liquid can be improved.

1. An inhaler comprising: a piezoelectric element substrate having anIDT constructed by use of a pair of interlocking comb-shaped metallicelectrodes; a liquid supplier for supplying liquid, which is to beatomized, to a front surface of the piezoelectric element substrate onwhich the pair of interlocking comb-shaped metallic electrodes ispositioned; a sensor, which comprises at least a pair of detection partswhich are opposite to each other, for detecting liquid supplied to thefront surface of the piezoelectric element substrate; and a controllerfor controlling, based on result of detection by the sensor, the liquidsupplier in such a manner that the liquid supplier supplies a certainquantity of the liquid to the front surface of the piezoelectric elementsubstrate.
 2. The inhaler according to claim 1, wherein the detectionparts are positioned apart from the front surface of the piezoelectricelement substrate.
 3. The inhaler according to claim 1, wherein thepiezoelectric element substrate comprises an edge to which the liquidfrom the liquid supplier is supplied; each of the detection partscomprises a convex part which projects toward an opposite detectionpart; and a distance between the edge and the convex part is 0.10 mm to0.20 mm.
 4. The inhaler according to claim 3, further comprising: aguide wall positioned at an edge side of the piezoelectric elementsubstrate; wherein a distance between the edge and an end surface, atthe edge side, of the guide wall is equal to or longer than 0.25 mm. 5.The inhaler according to claim 3, wherein a distance between the convexparts of the detection parts, which are opposite to each other,corresponds to an overlap length of the pair of interlocking comb-shapedmetallic electrodes.
 6. The inhaler according to claim 1, wherein thepiezoelectric element substrate comprises edges that are opposite toeach other across the pair of interlocking comb-shaped metallicelectrodes, and the sensor is arranged on each of the edges that areopposite to each other.
 7. The inhaler according to claim 1, wherein thesensor comprises one of an electric conductivity sensor, anemitter-receiver sensor, and a capacitive sensor.